[buy*david]

I have a Cubcadet walk behind mower with a knock off china type Honda motor.
It kicks back when trying to start. I checked timing, adjusted valves, and the blade is tight. It feels like the compression release isn't working, but it is opening the exhaust valve, I checked it. I had another mower with the same engine, same problem and adjusting the valves worked for it. It's not working for this one. The only insight is the manual says to pull the rope slowly until it's on compression then pull rapidly. This works to start without kick back, but it still feels like the compression release isn't releasing. I read some forums with other people having the same problem so it seems common and I hope someone has a solution. Has anyone had this problem and found a solution? It's a Model 898720 11a-18mz256 173cc 11070fua0609193a264 6.75 HP OHV
Thanks

 

[usmcgrunt]

Did you pull the fly wheel off and check for partially sheared key on the crank shaft?Just a thought,since you checked the most likely problems.

 

[buy*david]

Hey Grunt, yes I did check the flywheel key. It was one of the last things I did because it seemed to want to kickback even with the spark plug wire off. So I couldn't see it being that, but after everything else failed I did check it and the key is good and in the correct position.
I'm still thinking the compression release bump on the cam isn't doing it's job. It is opening the exhaust valve, but maybe it isn't enough.Do you know the lift required for it?

Thanks, David

 

[buy*david]

Thanks for the help, I finally got it. I set the valve adjustment to .13mm instead of .15mm and it works fine.That's only 1 or 2 thousandths so it must have been wear probably on the compression release bump or maybe flex in some of the other valve train components. But it's working and that's good enough for me, no kickback at all. Thanks

 

[usmcgrunt]

Good Job. Thank you for posting how you fixed it.:thumbsup:

 

[buy*david]

You're welcome. Some times just writing the post helps me think it threw. And I know what you mean, getting the fix out there is the most important part.