No start. Have gas, spark, compression

[kcsnapper]

Update: Finished tearing it down today. I found the valve guide on the exhaust to be 3/16" above the casting and the intake 1/4" above the casting. Also the intake pushrod is badly bent. Neither one of the valve guides seem to be loose but maybe that is something that is not readily seen. Additionally, I see that the intake valve guide is sticking down into the combustion chamber 5/16". If I lower the valve guide height on the spring side it is going to make the combustion side 7/8" Isn't that getting close to the top of the piston? I'm concerned about how that pushrod got bent and whether any other damage might have occurred.

John

 

[Tinkerer200]

"If I lower the valve guide height on the spring side it is going to make the combustion side 7/8" Isn't that getting close to the top of the piston? I'm concerned about how that pushrod got bent and whether any other damage might have occurred."

How is the valve guide going to get past the valve to get to the piston? I told you what B&S says about valve guide height. Of course the valve guide is not going to be "finger" loose. The push rod will bend for a couple of reasons. The aluminum intake valve push rod may wear a thin area where it rides on the fiber guide and be weakened until it bends. More likely the valve guide moves up until the valve spring keeper hits the top of the valve guide bending the push rod as it tries to open the valve. Occasionally the valve may stick causing the push rod to bend as it tries to open the stuck valve.

Walt Conner

 

[kcsnapper]

How is the valve guide going to get past the valve to get to the piston?

Walt Conner

Good point. I wasn't thinking there.

I solved the problem with a new head, valves, springs, guides etc. I couldn't find anyone local with the correct tooling (or desire) to do the job. I did find that the old valve caps were worn way down probably causing a severe valve maladjustment. It finally just shook itself apart bending the push rod and breaking the rocker.

One other question about the valve adjustment. I went by the service manual to set the valves and I'm pretty certain that they are correct. I turned the cylinder over and rechecked the settings 3 times. Problem that is bothering though is the torque value on the adjustment lock screw. I don't have an allen wrench bit that will fit on my torque wrench. How critical is the torque here? I would think that under-tightened would cause it to come loose. What is the consequence to having it too tight?
I may have to make a trip to town to pick up another tool.

John

 

[kcsnapper]

OK, answering my own question; If it wasn't important there wouldn't be a torque value for it. I got a proper allen wrench to fit on my 3/8 torque wrench and re-did the lock screw. I actually think I wasn't too far off.

So, then I turned the key to start it up and it started right up. I was at first impressed but now I have a governor/speed problem. I can't get it to idle down at all. At first the linkage was jammed but I got it straightened out so the cable goes in and out properly and the choke lever closes. I can start it and control the speed with the throttle on top of the carb. If I push the governor linkage forward it will move the throttle lever and it appears that the spring is still hooked up correctly. I'm going to the manual but I thought that I would post the problem here also.

Thanks,
John

 

[Tinkerer200]

Might check out the part on "Static Governor Setting".

Walt Conner

 

[kcsnapper]

Might check out the part on "Static Governor Setting".

Walt Conner

I found a bent throttle control rod, the one that connects the governor to the throttle valve. Straightened it the best I could and now it works correctly. Time to mow.

Thanks for your help.

John