Engine kick backs - Cord Pulls Out Of Your Hand

[Hammermechanicman]

I have the same problem with a Briggs from a Toro mower. I noticed someone mentioned a question of if there is a blade on or not. I've been trying g to start this with no blade and the kick back almost broke my fingers. I've been in pain e for a week now.

Is not having a blade on really that big of a deal?

Thanks

Some engines will start and run with no blade others won't. Most Briggs especially the old flat head engines will run wothout a blade. Most tecumseh engines won't.

 

[sallyphilip]

I had the same kickback problem with a Tecumseh engine on a Coleman Powermate generator. The kickback was so violent that it damaged the recoil starter and I had to replace it.

The problem turned out to be the stud (bolt) that the exhaust valve rocker sits on. This bolt had started to work loose, jacking up the rocker and affecting the exhaust valve clearance and timing. Once I tightened it properly and readjusted the valve lash, the engine started normally and ran like a top. I used four thousandths of an inch for the valve lash.

out of time

 

[slomo]

Carb might be dumping fuel into the cylinder = hydrolocking it. Pull the spark plug out and pull the rope. See if any liquids come out of the spark plug hole. If so, smell the liquid/s for identification.

slomo

 

[rainmaninwa]

Pull the flywheel, If this is truly an old briggs with point type ignition, all you need to do is open up the point gap a bit. I had exactly the same problem with my garage sale 5 hp briggs. Probably needs new point/condender anyhow...

 

[docnhy]

Hi!
I have a Briggs & Stratton 5HP that I recently bought second hand. The problem is that the cord is being pulled back really hard quite often when I try to start it. My father is quite good with engines and have disassemble it and we still don't know what the problem is.

The flywheel key is not broken and the 2 vents seems to be good so we are planning on grinding the vents and put everything back. We also thought if the ignition coil has moved so it ignite to early but that didn't seem to be the case.

Does any of you have any ideas of what the problem could be?

Thanks!

Broke flywheel keyway

 

[Gord Baker]

Hi!
I have a Briggs & Stratton 5HP that I recently bought second hand. The problem is that the cord is being pulled back really hard quite often when I try to start it. My father is quite good with engines and have disassemble it and we still don't know what the problem is.

The flywheel key is not broken and the 2 vents seems to be good so we are planning on grinding the vents and put everything back. We also thought if the ignition coil has moved so it ignite to early but that didn't seem to be the case.

Does any of you have any ideas of what the problem could be?

Thanks!

Take the top off down to the Flywheel and check under that nut to be sure that the Key has not been partially sheared which puts it out of time enough to do that . Did you remove the flywheel and examine the key? Set coil at 0.300" from Flywheel. It could be valve timing

 

[Hammermechanicman]

Set coil at 0.300" from Flywheel. It could be valve timing

0.300" ???????

 

[glensto68]

Most of the time the flywheel key is sheared when that begins to happen

 

[donens2018]

Almost positive the problem is timing and the flywheel key. The key doesn't have to be sheared off. A slight offset of the key will result is this condition. Also check the flywheel keyway for rounded edges which can add to early key shearing, even with a new key. Sometimes some extra torque on the flywheel nut or rewind clutch can help prevent. If at anytime during startup, if backfires, this can cause the flywheel to shear again.

 

[rminnehan]

Hi!
I have a Briggs & Stratton 5HP that I recently bought second hand. The problem is that the cord is being pulled back really hard quite often when I try to start it. My father is quite good with engines and have disassemble it and we still don't know what the problem is.

The flywheel key is not broken and the 2 vents seems to be good so we are planning on grinding the vents and put everything back. We also thought if the ignition coil has moved so it ignite to early but that didn't seem to be the case.

Does any of you have any ideas of what the problem could be?

Thanks!

The carburetor needle valve is not sealing tight and is letting gas go into the cylinder on top of the piston. When the piston reaches TDC (top dead center) the piston will not compress a liquid (the gasoline) as opposed to a vapor, which would be the gas/air mixture used for combustion. So when the piston reaches TDC the gasoline between the top of the piston and the head causes the piston to stop and it kicks back, jerking the starter line from your hand and damn near tearing your shoulder off. You need to do 3 things: First, fix the carburetor so the needle valve won't continue to leak. Second, remove the spark plug and pull the engine over. Be careful when doing this as gasoline will spew out the spark plug hole so try to put a rag or paper towel in front of the hole. Third, the gasoline that goes through the carburetor when the needle valve is leaking sometimes also goes into the crankcase and dilutes the oil in it so change the oil.