Kevin Ricks wrote:
Bill wrote:
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.