I had a honda lawn mower that had a bent crankshaft. I ordered a new shaft and put it in. However, after putting the engine back together it is kicking back when I try to start it. I timed the cam the way I have read that you should do with the piston being at TDC and the two marks on the cam gear being parallel with the the block. It will start and runs fine but sometimes when trying to start it, it will try to pull your shoulder out of its socket. Would having the belt one notch either too slow or too fast cause this? It has got me beat as I have tried everything I can think of and can't seem to eliminate the kicking back. I did check and the decompression arm is opening the exhaust valve up just a little bit to relieve the compression. Any help would be greatly appreciated.
Honda Mower Seems to be out of time
- Thread starter Rednec
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bertsmobile1
Lawn Royalty
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- Nov 29, 2014
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If the jerk back is associated with a pop or bang then it is out of time
If it just stops dead then recoils then the decompressor is not working.
They feel very similar.
the first is because the engine is firing at the wrong time so you just get a jerk while the rope is pulling
The second is because you can not get the piston over TDG so it gets harder to pull then stops then pulls back.
In the timing case it will be because the engine is too far advanced.
A split or broken timing key in the flywheel will do the same thing so check it before you go ripping into the engine again.
If it just stops dead then recoils then the decompressor is not working.
They feel very similar.
the first is because the engine is firing at the wrong time so you just get a jerk while the rope is pulling
The second is because you can not get the piston over TDG so it gets harder to pull then stops then pulls back.
In the timing case it will be because the engine is too far advanced.
A split or broken timing key in the flywheel will do the same thing so check it before you go ripping into the engine again.
I had the key out when I replaced the crank and didn't notice anything wrong with it. I did find it a little strange that it appeared to be steel not an aluminum one like in most Briggs engines. With the valve cover off and the plug out I have rotated the engine several times and the decompressor appears to be working in that it appears it opens the exhaust valve maybe an 1/8 of an inch. Do you think if I advanced the timing gear one notch on the belt it would possibly open the exhaust valve a little quicker and therefore it would not kickback? I'm not even sure if it would run in that position or not as I tried to set it up just like it says to put it in time. It runs great when you can finally get it passed the hard spot and get it to start. I failed to mention that there is no popping or anything noise at all when it does this other than me uttering a few choice words when it jerks the cord out of my hand.
No the blade is attached although the mower does have a blade clutch so the blade isn't actually turning when trying to start it. It is a GVC 190 engine. The funny thing about this is it didn't do this before I replaced the crankshaft.
I will try that tomorrow. I talked to the guy I got the mower from (the one that bent the crankshaft) and he said he never had any problem with it doing anything like this before he hit something and bent the crank.
I think Bert is referring to spark timing, not cam angle. The spark timing would be affected by flywheel key , different flywheel, loose flywheel , different coil pickup geometry, loose coil mounting? On Briggs V engine I can hook up an auto lite and it will fire dull red in a darkened garage. Since there is no advance (Honda?)when the engine turns fast enough to generate spark you could see where timing is, but you must first mark TDC.
Do you know if I advance the cam one or two notches on the belt wouldn't that retired the timing? Also, do you know how many notches I could move it and it still run? Thanks