10.5 hp engine kicks-back when starting sometimes!

[Bill]

I have a 10.5 hp gasoline engine on my wood splitter which sometimes kicks
back when I pull the rope to start it. (Just once every few days, but that
is once too many times.)

This kicks back with a lot of force! And I am pulling with a lot of force as
well! Not good. (I've noticed this same problem with smaller engines too,
but not so much kick back force, so no problem there.)

I got to thinking that I was going to break or injure my hand/arm if I kept
starting this engine. I searched the internet for injuries from starting
these larger engines and there were in fact quite a few injuries including
some broken bones. So I decided to solve this problem by installing an
electric start. No more problem now for me...

But I got to thinking about this and why this happens. And could something
be done to prevent this? (And the reason I am posting this.) A lot of you on
these groups are quite clever, so maybe someone can come up with
something...

I think the problem is that the spark is firing right when the piston
reaches the top of the stroke or slightly before it reaches the top. Then
sometimes this will cause the piston to go backwards instead of forwards.
(And it needs to be this way of course to run properly.)

My idea is to delay the spark just a little for starting. There could be a
switch to start an engine which delays the spark. Then once the engine is
running, you would flip the switch and it would spark and run like normal.
But when starting, kickback would be impossible because it would not spark
until the piston was its the way down.

Anyway I thought I would pass this idea along. Maybe some rocket scientist
out there could come up with something which would attach between the spark
plug and the spark plug wire???

[Don Bruder]

Post by Bill
I have a 10.5 hp gasoline engine on my wood splitter which sometimes kicks
back when I pull the rope to start it. (Just once every few days, but that
is once too many times.)
This kicks back with a lot of force! And I am pulling with a lot of force as
well! Not good. (I've noticed this same problem with smaller engines too,
but not so much kick back force, so no problem there.)
I got to thinking that I was going to break or injure my hand/arm if I kept
starting this engine. I searched the internet for injuries from starting
these larger engines and there were in fact quite a few injuries including
some broken bones. So I decided to solve this problem by installing an
electric start. No more problem now for me...
But I got to thinking about this and why this happens. And could something
be done to prevent this? (And the reason I am posting this.) A lot of you on
these groups are quite clever, so maybe someone can come up with
something...
I think the problem is that the spark is firing right when the piston
reaches the top of the stroke or slightly before it reaches the top. Then
sometimes this will cause the piston to go backwards instead of forwards.
(And it needs to be this way of course to run properly.)
My idea is to delay the spark just a little for starting. There could be a
switch to start an engine which delays the spark. Then once the engine is
running, you would flip the switch and it would spark and run like normal.
But when starting, kickback would be impossible because it would not spark
until the piston was its the way down.
Anyway I thought I would pass this idea along. Maybe some rocket scientist
out there could come up with something which would attach between the spark
plug and the spark plug wire???

Good plan - Called "variable timing", and used on the Model T, for
exactly the same purpose/reason, if I recall rightly. But I'll be dipped
if I can tell you what the exact mechanism was.

But it's just plain NOT going to happen by putting something between the
plug and the wire - It's something that has to be done at a "lower
level".

Most "lawn-mower type" engines fire by way of a coil (or two coils, in
the case of a two-cylinder rig) bolted solidly to the block (which means
no adjusting of spark advance/retard is possible without major surgery)
with a magnet in the flywheel passing under it. And since the flywheel
is almost invariably keyed onto the crankshaft to maintain timing,
that's also almost impossible to alter without major surgery.

Adjusting spark timing is dead-simple on a car, or other distributor-fed
engine, since all it takes is twisting the distributor a bit. Doing it
on a coil-and-magnet rig like most small engines is nearly impossible
unless the capability was designed in right from the start.

[AZ Nomad]

Post by Don Bruder
Good plan - Called "variable timing", and used on the Model T, for
exactly the same purpose/reason, if I recall rightly. But I'll be dipped
if I can tell you what the exact mechanism was.

Retard the ignition timing by rotating the distributor?
Model T's used a buzzerbox to generate high voltage, so I don't know their
mechanism exactly.

Post by Don Bruder
But it's just plain NOT going to happen by putting something between the
plug and the wire - It's something that has to be done at a "lower
level".

No, the location where the crank angle is detected (ie: where the points
live or where there's a magneto) would have to be turned.

Post by Don Bruder
Most "lawn-mower type" engines fire by way of a coil (or two coils, in
the case of a two-cylinder rig) bolted solidly to the block (which means
no adjusting of spark advance/retard is possible without major surgery)
with a magnet in the flywheel passing under it. And since the flywheel
is almost invariably keyed onto the crankshaft to maintain timing,
that's also almost impossible to alter without major surgery.

A fixed coil with a magnet on the flywheel would be difficult to modify.
Maybe the flywheel or coil has shifted?

Post by Don Bruder
Adjusting spark timing is dead-simple on a car, or other distributor-fed
engine, since all it takes is twisting the distributor a bit. Doing it
on a coil-and-magnet rig like most small engines is nearly impossible
unless the capability was designed in right from the start.

Maybe it's experiencing pre-ignition or incredibly late ignition. Replacing the
sparkplug might be a good start.

[Ann]

<...>

Post by Bill
Anyway I thought I would pass this idea along. Maybe some rocket
scientist out there could come up with something which would attach
between the spark plug and the spark plug wire???

Good plan - Called "variable timing", and used on the Model T, for exactly
the same purpose/reason, if I recall rightly. But I'll be dipped if I can
tell you what the exact mechanism was.

My grandfather's Model A pickup had a retard spark lever on the steering
column. I Googled to confirm (yes) but didn't wade through the
explanation(s).

<...>

[Neon John]

Post by Bill
I have a 10.5 hp gasoline engine on my wood splitter which sometimes kicks
back when I pull the rope to start it. (Just once every few days, but that
is once too many times.)
This kicks back with a lot of force! And I am pulling with a lot of force as
well! Not good. (I've noticed this same problem with smaller engines too,
but not so much kick back force, so no problem there.)
My idea is to delay the spark just a little for starting. There could be a
switch to start an engine which delays the spark. Then once the engine is
running, you would flip the switch and it would spark and run like normal.
But when starting, kickback would be impossible because it would not spark
until the piston was its the way down.

Most, perhaps all modern engines already have electronic start retard built
into the electronic ignition module. (if your engine is old enough to still
have points, all bets are off.)

Start retard can only go so far. Many folks had their arms broken trying to
start Model As even with the manual retard set full retard. Ditto ankles and
old motorcycles with manual retard. I can count myself in the "almost"
category. Which brings me around to my main point.

The problem isn't with the engine. It's with the starting technique. Any
engine will kick back if the crankshaft is turning slowly enough when the
spark fires that it can't make it over TDC before burning gets underway. This
happens when you grab the cord and yank or stomp the kick starter from some
random engine condition without setting things up first. That's why one never
lets that happen.

The technique, developed around the turn of the previous century, is to slowly
rotate the engine until the piston is at top dead center on the power stroke.
That's where the crank suddenly rotates freely a little bit after the
resistance of compression.

After the engine is positioned that way, the cord is retracted (or the kick
starter returned to rest) and the strongest pull you can muster is given. The
engine has almost two complete rotations to store energy in the flywheel
before the compression stroke is encountered.

The result is an easier pull, no chance of kickback and usually, starting on
the first pull. One must be sure to immediately return the starter cord to
the rest position (don't let it fly - the recoil spring and/or rope will
eventually break from that abuse). If you hold onto the cord and the engine
doesn't quite start but fires in reverse, it'll yank the cord out of your hand
rather violently. Blisters and ripped skin can result.

I used to ride and race big single cylinder bikes before electric starters
become available. The "find TDC before cranking" became so second nature that
I now automatically do it even with tiny engines like the one on my weed
whacker. Not chance of kickback there, at least none that matters, but
pulling the cord is sooooo much less effort that way.

John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
What do you call a blonde's cranial cavity? Vacuum chamber?

[Jim]

Neon John wrote:
[....]

Post by Neon John
The problem isn't with the engine. It's with the starting technique. Any
engine will kick back if the crankshaft is turning slowly enough when the
spark fires that it can't make it over TDC before burning gets underway. This
happens when you grab the cord and yank or stomp the kick starter from some
random engine condition without setting things up first. That's why one never
lets that happen.
The technique, developed around the turn of the previous century, is to slowly
rotate the engine until the piston is at top dead center on the power stroke.
That's where the crank suddenly rotates freely a little bit after the
resistance of compression.
After the engine is positioned that way, the cord is retracted (or the kick
starter returned to rest) and the strongest pull you can muster is given. The
engine has almost two complete rotations to store energy in the flywheel
before the compression stroke is encountered.
The result is an easier pull, no chance of kickback and usually, starting on
the first pull. One must be sure to immediately return the starter cord to
the rest position (don't let it fly - the recoil spring and/or rope will
eventually break from that abuse). If you hold onto the cord and the engine
doesn't quite start but fires in reverse, it'll yank the cord out of your hand
rather violently. Blisters and ripped skin can result.
I used to ride and race big single cylinder bikes before electric starters
become available. The "find TDC before cranking" became so second nature that
I now automatically do it even with tiny engines like the one on my weed
whacker. Not chance of kickback there, at least none that matters, but
pulling the cord is sooooo much less effort that way.
John

good write-up John. facts are always useful.

[Sheldon]

Post by Bill
I have a 10.5 hp gasoline engine on my wood splitter which sometimes kicks
back when I pull the rope to start it. (Just once every few days, but that
is once too many times.)
This kicks back with a lot of force! And I am pulling with a lot of force as
well! Not good. (I've noticed this same problem with smaller engines too,
but not so much kick back force, so no problem there.)
I got to thinking that I was going to break or injure my hand/arm if I kept
starting this engine. I searched the internet for injuries from starting
these larger engines and there were in fact quite a few injuries including
some broken bones. So I decided to solve this problem by installing an
electric start. No more problem now for me...
But I got to thinking about this and why this happens. And could something
be done to prevent this? (And the reason I am posting this.) A lot of you on
these groups are quite clever, so maybe someone can come up with
something...
I think the problem is that the spark is firing right when the piston
reaches the top of the stroke or slightly before it reaches the top. Then
sometimes this will cause the piston to go backwards instead of forwards.
(And it needs to be this way of course to run properly.)
My idea is to delay the spark just a little for starting. There could be a
switch to start an engine which delays the spark. Then once the engine is
running, you would flip the switch and it would spark and run like normal.
But when starting, kickback would be impossible because it would not spark
until the piston was its the way down.
Anyway I thought I would pass this idea along. Maybe some rocket scientist
out there could come up with something which would attach between the spark
plug and the spark plug wire???

You're having the same problem with other engines... so it's not the
engines, it's you. Get yourself to a small engine repair shop and ask/
beg someone to instruct you in the proper method for pulling that
rope.. Are you left handed?

[u***@gmail.com]

Sheldon I just saw your post and respectfully disagree and I have experience the Sam issues .

While not having this issue on a similar type pullstart .
The issue is the timing is probably off causing the kickback .
There should be a compression relaease and if it’s not working then it probably needs to be refined .
Also check the shear key so see if is lined up on the wheel key .

[Steve Barker DLT]

is this only on a hot engine, or on a cold one also? If only on a hot
engine, you might try a midgrade fuel. You may be getting some pre-ignition
from the shitty fuel we have today.

steve

Post by Bill
I have a 10.5 hp gasoline engine on my wood splitter which sometimes kicks
back when I pull the rope to start it. (Just once every few days, but that
is once too many times.)
This kicks back with a lot of force! And I am pulling with a lot of force
as well! Not good. (I've noticed this same problem with smaller engines
too, but not so much kick back force, so no problem there.)
I got to thinking that I was going to break or injure my hand/arm if I
kept starting this engine. I searched the internet for injuries from
starting these larger engines and there were in fact quite a few injuries
including some broken bones. So I decided to solve this problem by
installing an electric start. No more problem now for me...
But I got to thinking about this and why this happens. And could something
be done to prevent this? (And the reason I am posting this.) A lot of you
on these groups are quite clever, so maybe someone can come up with
something...
I think the problem is that the spark is firing right when the piston
reaches the top of the stroke or slightly before it reaches the top. Then
sometimes this will cause the piston to go backwards instead of forwards.
(And it needs to be this way of course to run properly.)
My idea is to delay the spark just a little for starting. There could be a
switch to start an engine which delays the spark. Then once the engine is
running, you would flip the switch and it would spark and run like normal.
But when starting, kickback would be impossible because it would not spark
until the piston was its the way down.
Anyway I thought I would pass this idea along. Maybe some rocket scientist
out there could come up with something which would attach between the
spark plug and the spark plug wire???

[HeyBub]

Post by Steve Barker DLT
is this only on a hot engine, or on a cold one also? If only on a hot
engine, you might try a midgrade fuel. You may be getting some
pre-ignition from the shitty fuel we have today.

Good point. The lower the octane the higher the volatility. Higher octane
gas has a higher ignition point and is harder to detonate.

[ransley]

Post by Bill
I have a 10.5 hp gasoline engine on my wood splitter which sometimes kicks
back when I pull the rope to start it. (Just once every few days, but that
is once too many times.)
This kicks back with a lot of force! And I am pulling with a lot of force as
well! Not good. (I've noticed this same problem with smaller engines too,
but not so much kick back force, so no problem there.)
I got to thinking that I was going to break or injure my hand/arm if I kept
starting this engine. I searched the internet for injuries from starting
these larger engines and there were in fact quite a few injuries including
some broken bones. So I decided to solve this problem by installing an
electric start. No more problem now for me...
But I got to thinking about this and why this happens. And could something
be done to prevent this? (And the reason I am posting this.) A lot of you on
these groups are quite clever, so maybe someone can come up with
something...
I think the problem is that the spark is firing right when the piston
reaches the top of the stroke or slightly before it reaches the top. Then
sometimes this will cause the piston to go backwards instead of forwards.
(And it needs to be this way of course to run properly.)
My idea is to delay the spark just a little for starting. There could be a
switch to start an engine which delays the spark. Then once the engine is
running, you would flip the switch and it would spark and run like normal.
But when starting, kickback would be impossible because it would not spark
until the piston was its the way down.
Anyway I thought I would pass this idea along. Maybe some rocket scientist
out there could come up with something which would attach between the spark
plug and the spark plug wire???

Maybe the timing is off from Pin Shear

[ransley]

Post by Bill
I have a 10.5 hp gasoline engine on my wood splitter which sometimes kicks
back when I pull the rope to start it. (Just once every few days, but that
is once too many times.)
This kicks back with a lot of force! And I am pulling with a lot of force as
well! Not good. (I've noticed this same problem with smaller engines too,
but not so much kick back force, so no problem there.)
I got to thinking that I was going to break or injure my hand/arm if I kept
starting this engine. I searched the internet for injuries from starting
these larger engines and there were in fact quite a few injuries including
some broken bones. So I decided to solve this problem by installing an
electric start. No more problem now for me...
But I got to thinking about this and why this happens. And could something
be done to prevent this? (And the reason I am posting this.) A lot of you on
these groups are quite clever, so maybe someone can come up with
something...
I think the problem is that the spark is firing right when the piston
reaches the top of the stroke or slightly before it reaches the top. Then
sometimes this will cause the piston to go backwards instead of forwards.
(And it needs to be this way of course to run properly.)
My idea is to delay the spark just a little for starting. There could be a
switch to start an engine which delays the spark. Then once the engine is
running, you would flip the switch and it would spark and run like normal.
But when starting, kickback would be impossible because it would not spark
until the piston was its the way down.
Anyway I thought I would pass this idea along. Maybe some rocket scientist
out there could come up with something which would attach between the spark
plug and the spark plug wire???

Maybe the timing is off from Pin Shear- Hide quoted text -
- Show quoted text -

By your lingo you are N. Canadian, I bet its Pin Shear = improper
timing , a bad or loose Pin on the shaft . Timing as you see and know
of is off, find out why , its mechanical. I bet it locked - knocked, a
few degrees off on a previous stallout to zero rpm, forcing the pin or
something else out of spec. A backfire never should happen, a
Backfire is bad timing = maybe Pin Shear. But im guessing, and never
worked on a motors issue. But I know fact of operation.. I still bet
its the Timing Pin-key on the Fly wheel, but a motor pro will know.

[NapalmHeart]

Post by Bill
I have a 10.5 hp gasoline engine on my wood splitter
which sometimes kicks
back when I pull the rope to start it. (Just once every
few days, but that
is once too many times.)
This kicks back with a lot of force! And I am pulling
with a lot of force as
well! Not good. (I've noticed this same problem with
smaller engines too,
but not so much kick back force, so no problem there.)
I got to thinking that I was going to break or injure my
hand/arm if I kept
starting this engine. I searched the internet for
injuries from starting
these larger engines and there were in fact quite a few
injuries including
some broken bones. So I decided to solve this problem by
installing an
electric start. No more problem now for me...
But I got to thinking about this and why this happens.
And could something
be done to prevent this? (And the reason I am posting
this.) A lot of you on
these groups are quite clever, so maybe someone can come
up with
something...
I think the problem is that the spark is firing right
when the piston
reaches the top of the stroke or slightly before it
reaches the top. Then
sometimes this will cause the piston to go backwards
instead of forwards.
(And it needs to be this way of course to run properly.)
My idea is to delay the spark just a little for
starting. There could be a
switch to start an engine which delays the spark. Then
once the engine is
running, you would flip the switch and it would spark
and run like normal.
But when starting, kickback would be impossible because
it would not spark
until the piston was its the way down.
Anyway I thought I would pass this idea along. Maybe
some rocket scientist
out there could come up with something which would
attach between the spark
plug and the spark plug wire???

Maybe the timing is off from Pin Shear- Hide quoted text -
- Show quoted text -

By your lingo you are N. Canadian, I bet its Pin Shear =
improper
timing , a bad or loose Pin on the shaft . Timing as you see
and know
of is off, find out why , its mechanical. I bet it locked -
knocked, a
few degrees off on a previous stallout to zero rpm, forcing
the pin or
something else out of spec. A backfire never should
happen, a
Backfire is bad timing = maybe Pin Shear. But im guessing,
and never
worked on a motors issue. But I know fact of operation.. I
still bet
its the Timing Pin-key on the Fly wheel, but a motor pro
will know.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The flyweights on the mechanical advance could be stuck in
an advanced position.

Ken

[Steve Barker DLT]

Mechanical advance? On a single cylinder 10.5 HP?? Ya, oooooooook........

s

Post by NapalmHeart
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The flyweights on the mechanical advance could be stuck in an advanced
position.
Ken

[NapalmHeart]

Post by Steve Barker DLT
Mechanical advance? On a single cylinder 10.5 HP?? Ya,
oooooooook........
s

Post by NapalmHeart
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The flyweights on the mechanical advance could be stuck
in an advanced position.
Ken

I've seen them on smaller engines than that, but if you
haven't, that's OK.

[Dean Hoffman]

Post by Bill
I have a 10.5 hp gasoline engine on my wood splitter which sometimes kicks
back when I pull the rope to start it. (Just once every few days, but that
is once too many times.)
This kicks back with a lot of force! And I am pulling with a lot of force as
well! Not good. (I've noticed this same problem with smaller engines too,
but not so much kick back force, so no problem there.)
I got to thinking that I was going to break or injure my hand/arm if I kept
starting this engine. I searched the internet for injuries from starting
these larger engines and there were in fact quite a few injuries including
some broken bones. So I decided to solve this problem by installing an
electric start. No more problem now for me...
But I got to thinking about this and why this happens. And could something
be done to prevent this? (And the reason I am posting this.) A lot of you on
these groups are quite clever, so maybe someone can come up with
something...
I think the problem is that the spark is firing right when the piston
reaches the top of the stroke or slightly before it reaches the top. Then
sometimes this will cause the piston to go backwards instead of forwards.
(And it needs to be this way of course to run properly.)
My idea is to delay the spark just a little for starting. There could be a
switch to start an engine which delays the spark. Then once the engine is
running, you would flip the switch and it would spark and run like normal.
But when starting, kickback would be impossible because it would not spark
until the piston was its the way down.
Anyway I thought I would pass this idea along. Maybe some rocket scientist
out there could come up with something which would attach between the spark
plug and the spark plug wire???

You need to teach that engine some respect. Some use big and
bigger hammers. One guy used another way: http://tinyurl.com/6ftwow

Dean


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[Kevin Ricks]

Post by Bill
I have a 10.5 hp gasoline engine on my wood splitter which sometimes kicks
back when I pull the rope to start it. (Just once every few days, but that
is once too many times.)
This kicks back with a lot of force! And I am pulling with a lot of force as
well! Not good. (I've noticed this same problem with smaller engines too,
but not so much kick back force, so no problem there.)
I got to thinking that I was going to break or injure my hand/arm if I kept
starting this engine. I searched the internet for injuries from starting
these larger engines and there were in fact quite a few injuries including
some broken bones. So I decided to solve this problem by installing an
electric start. No more problem now for me...
But I got to thinking about this and why this happens. And could something
be done to prevent this? (And the reason I am posting this.) A lot of you on
these groups are quite clever, so maybe someone can come up with
something...
I think the problem is that the spark is firing right when the piston
reaches the top of the stroke or slightly before it reaches the top. Then
sometimes this will cause the piston to go backwards instead of forwards.
(And it needs to be this way of course to run properly.)
My idea is to delay the spark just a little for starting. There could be a
switch to start an engine which delays the spark. Then once the engine is
running, you would flip the switch and it would spark and run like normal.
But when starting, kickback would be impossible because it would not spark
until the piston was its the way down.
Anyway I thought I would pass this idea along. Maybe some rocket scientist
out there could come up with something which would attach between the spark
plug and the spark plug wire???

This is how I start a motor, maybe I just learned to do this to avoid
kickback I don't know?
Pull the rope full travel or as much as possible. Don't short stroke it.
Let the starter rope retract quickly, Don't stand there holding the rope
handle. On a no start don't start the next pull until the engine has
completely stopped turning.
If I sense a kickback, I just let go of the handle.

Also the starter catch mechanism may need to be lubricated so that it
disengages properly.

Kevin

[Sheldon]

Post by Kevin Ricks

Post by Bill
I have a 10.5 hp gasoline engine on my wood splitter which sometimes kicks
back when I pull the rope to start it. (Just once every few days, but that
is once too many times.)
This kicks back with a lot of force! And I am pulling with a lot of force as
well! Not good. (I've noticed this same problem with smaller engines too,
but not so much kick back force, so no problem there.)
I got to thinking that I was going to break or injure my hand/arm if I kept
starting this engine. I searched the internet for injuries from starting
these larger engines and there were in fact quite a few injuries including
some broken bones. So I decided to solve this problem by installing an
electric start. No more problem now for me...
But I got to thinking about this and why this happens. And could something
be done to prevent this? (And the reason I am posting this.) A lot of you on
these groups are quite clever, so maybe someone can come up with
something...
I think the problem is that the spark is firing right when the piston
reaches the top of the stroke or slightly before it reaches the top. Then
sometimes this will cause the piston to go backwards instead of forwards.
(And it needs to be this way of course to run properly.)
My idea is to delay the spark just a little for starting. There could be a
switch to start an engine which delays the spark. Then once the engine is
running, you would flip the switch and it would spark and run like normal.
But when starting, kickback would be impossible because it would not spark
until the piston was its the way down.
Anyway I thought I would pass this idea along. Maybe some rocket scientist
out there could come up with something which would attach between the spark
plug and the spark plug wire???

This is how I start a motor, maybe I just learned to do this to avoid
kickback I don't know?
Pull the rope full travel or as much as possible. Don't short stroke it.
Let the starter rope retract quickly, Don't stand there holding the rope
handle. On a no start don't start the next pull until the engine has
completely stopped turning.
If I sense a kickback, I just let go of the handle.
Also the starter catch mechanism may need to be lubricated so that it
disengages properly.

It's often more than a mere catch mechanism. With many of the pull
start motors sold within the last ten years pulling the rope does not
start the motor directly, pulling the rope winds a spring that once a
particular pre-set tension is reached the spring releases and that's
what rotates the flywheel... so that it rotates at a greater velocity
than one can yank a cord by hand ... it's actually tantamont to
electric start because pulling the cord essentially loads a starter
motor, albeit spring loaded. With these motors the spring is wound
with several short partial pulls of the cord and with progressively
more pressure... with a little practice one will feel how
progressively more pressure is required with each subsequent shorter
pull as the spring tension increases and each subsequent pull should
be shorter and shorter, it won't be too long before one will sense
exactly when the spring will release (guys should be especially good
at this sensing when it's approaching the point of no return, if yoose
get my drift), if full pulls are made mindlessly the spring will
release mid pull (prematurely) so kickback will typically occur, often
painful. Read the manual paying careful attention to the section on
starting... often manuals are not very clear so it's best to have
someone at a small motor repair shop demonstrate. And typically
lefties have trouble with pull start motors, not all, but generally,
because like most all machine tools they are designed for righties.

[Steve Barker DLT]

Very very few recoil starters work this way. In fact, i believe Stihl is
the only one doing that on small chainsaws. And they only started that a
couple years ago.

s

Post by Sheldon
It's often more than a mere catch mechanism. With many of the pull
start motors sold within the last ten years pulling the rope does not
start the motor directly, pulling the rope winds a spring that once a
particular pre-set tension is reached the spring releases and that's
what rotates the flywheel...

[Kole Walker]

Im a chain saw master tech certified in sthil it's called "elasto start"
It could your "key" on the flywheel. Basicly your coil is a fixed unit
but i suspect some timing issue for sure check the exhaust valve(s)
might be a little slow (carbon build up) and yes the fuel today is'nt
worth beans good luck Chopper at Big bear City Saw Works in CA

[KLS]

Post by Kevin Ricks
This is how I start a motor, maybe I just learned to do this to avoid
kickback I don't know?

I also learned this technique somehow; maybe a friend suggested I try
it one time?

Post by Kevin Ricks
Pull the rope full travel or as much as possible. Don't short stroke it.
Let the starter rope retract quickly, Don't stand there holding the rope
handle. On a no start don't start the next pull until the engine has
completely stopped turning.
If I sense a kickback, I just let go of the handle.

Exactly what I do, and works great for my small engines. That first
pull is not a yank, it's a slow deliberate pull of the entire rope.
Highly recommended.

[terry]

Post by KLS

Post by Kevin Ricks
This is how I start a motor, maybe I just learned to do this to avoid
kickback I don't know?

I also learned this technique somehow; maybe a friend suggested I try
it one time?  

Post by Kevin Ricks
Pull the rope full travel or as much as possible. Don't short stroke it.
Let the starter rope retract quickly, Don't stand there holding the rope
handle. On a no start don't start the next pull until the engine has
completely stopped turning.
If I sense a kickback, I just let go of the handle.

Exactly what I do, and works great for my small engines.  That first
pull is not a yank, it's a slow deliberate pull of the entire rope.
Highly recommended.

Old auto engines.
Started by hand crank. Some had no electric starters at all. We had a
1926 Daimler hearse refitted with a 1938 Bedford (i.e. UK GMC).
straight six engine, that had a defective starter AND a weak 1936
battery that had to be started by hand!
Ignition off.
Turn over engine slowly by hand through compressions of several or all
cylinders to draw mixture into cylinders.
Retard ignition timing; by the control often mounted on middle of the
steering wheel.
Pull compression up to near TDC.
Ignition on.
Pull by hand over TDC (watch your thumb position) and engine should
start.
Adjust ignition timing and drive off.

[j***@gmail.com]

Post by terry

Post by KLS

Post by Kevin Ricks
This is how I start a motor, maybe I just learned to do this to avoid
kickback I don't know?

I also learned this technique somehow; maybe a friend suggested I try
it one time?  

Post by Kevin Ricks
Pull the rope full travel or as much as possible. Don't short stroke it.
Let the starter rope retract quickly, Don't stand there holding the rope
handle. On a no start don't start the next pull until the engine has
completely stopped turning.
If I sense a kickback, I just let go of the handle.

Exactly what I do, and works great for my small engines.  That first
pull is not a yank, it's a slow deliberate pull of the entire rope.
Highly recommended.

Old auto engines.
Started by hand crank. Some had no electric starters at all. We had a
1926 Daimler hearse refitted with a 1938 Bedford (i.e. UK GMC).
straight six engine, that had a defective starter AND a weak 1936
battery that had to be started by hand!
Ignition off.
Turn over engine slowly by hand through compressions of several or all
cylinders to draw mixture into cylinders.
Retard ignition timing; by the control often mounted on middle of the
steering wheel.
Pull compression up to near TDC.
Ignition on.
Pull by hand over TDC (watch your thumb position) and engine should
start.
Adjust ignition timing and drive off.

Fascinating! I've had several engines with devices that retarded the timing so that ignition occurred with the piston on the compression stroke close to top dead center: 4-cylinder A-65 Continental on an old '46 Taylorcraft airplane, for example. I always hand-propped it on the Slick mag with the impulse coupling which retarded the timing to 5 deg. BTDC. Then once it was running I turned on the Bendix mag. Now the engine's mags are making sparks at 30 deg. BTDC, and timing is no longer adjustable. Only fuel mixture is adjustable in flight.

My old kick-start '61 Panhead had timing retarded by twisting the distributor. As soon as it was running, a spring on the twist lever would pull the distributor around to fully advanced timing. Sometimes in city traffic I would retard the timing just enough to stop spark knock from the heat of not getting enough air through the cooling fins, like waiting for a red light to turn green.

My old '68 BSA Spitfire also had a lever to retard timing, and another lever to adjust mixture.

Either one of these bikes would kick you over the handlebars, or bust the calf of your leg, if you did not watch how you started them.

It seems to me that the 10.5 hp engine would have some kind of automatic timing adjustment, or an automatic compression release to make starting easier. I have those devices on my old lawn mowers. And they're like me: old as dirt.

The object is to pull like hell, as fast as you can, to give the crankshaft enough momentum so that even when combustion occurs at 20 or 30 degrees BTDC, the crankshaft keeps rotating in the proper direction of rotation and does not kick back on you.

I've seen some younger guys hand-propping at the airport get hurt by not understanding those old magnetos, like the Bendix, which have no impulse couplings on them. All the line-boys at the airport are trained how to hand-prop, and they all wear thick gloves.

That wind-up device on the Stihl reminds me of some old aircraft tech where elbow grease was used to crank up a flywheel, storing up potential energy which is then released by a clutch to give a quick series of rotations to the crankshaft and start the engine. Some of those engines even used compressed gases from exploding cartridges about the size of shotgun shells to get an aircraft engine going. Remember that method in FLIGHT OF THE PHOENIX? They almost ran out of cartridges before the engine fired.

[j***@gmail.com]

Post by Bill
I have a 10.5 hp gasoline engine on my wood splitter which sometimes kicks
back when I pull the rope to start it. (Just once every few days, but that
is once too many times.)
This kicks back with a lot of force! And I am pulling with a lot of force as
well! Not good. (I've noticed this same problem with smaller engines too,
but not so much kick back force, so no problem there.)
I got to thinking that I was going to break or injure my hand/arm if I kept
starting this engine. I searched the internet for injuries from starting
these larger engines and there were in fact quite a few injuries including
some broken bones. So I decided to solve this problem by installing an
electric start. No more problem now for me...
But I got to thinking about this and why this happens. And could something
be done to prevent this? (And the reason I am posting this.) A lot of you on
these groups are quite clever, so maybe someone can come up with
something...
I think the problem is that the spark is firing right when the piston
reaches the top of the stroke or slightly before it reaches the top. Then
sometimes this will cause the piston to go backwards instead of forwards.
(And it needs to be this way of course to run properly.)
My idea is to delay the spark just a little for starting. There could be a
switch to start an engine which delays the spark. Then once the engine is
running, you would flip the switch and it would spark and run like normal.
But when starting, kickback would be impossible because it would not spark
until the piston was its the way down.
Anyway I thought I would pass this idea along. Maybe some rocket scientist
out there could come up with something which would attach between the spark
plug and the spark plug wire???

What is the name and model no. of the engine?

[Neon John]

Post by Bill
I have a 10.5 hp gasoline engine on my wood splitter which sometimes kicks
back when I pull the rope to start it. (Just once every few days, but that
is once too many times.)
This kicks back with a lot of force! And I am pulling with a lot of force as
well! Not good. (I've noticed this same problem with smaller engines too,
but not so much kick back force, so no problem there.)

Wrong technique. If you yank hard against the compression stroke, the
mix is likely to fire, driving the engine in reverse, spooling in the
starting cord at high speed and perhaps hurting your hand or arm.

Here's the correct method. Turn on the gas, ignition, set the choke
and whatever else you do to get the engine to run. Pull the cord
fairly gently until the flywheel goes through the compression stroke
and cams over at TD. Let the cord retract and give it a strong steady
pull, making sure you pull the rope almost all the way out.

This puts enough momentum in the flywheel that it will carry through
the next compression stroke and 9 out of 10 times the engine starts.

I have an emergency auto-start whole-house generator with a 27 Hp
propane fired engine. It's electric-start, of course, but it also has
a manual cranking rope just in case the battery runs down. Using this
technique, I can crank that large engine with almost no effort.

John
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address