pylek wrote:Alright, after a hiatus, I am back on this pushmower. I have pulled the head and valves. I cleaned most of the carbon from the head, piston, and valve area. I lapped the valves and set the clearances. Put it all back together with new gaskets. Couldn't find a listing for the intake pipe screw torque, so I used the general hardware spec.
Started the engine, no change...
Last night, I checked the spark while it was surging. Spark looked good at .165" on my tester. However, with a larger gap, the engine started to stutter, spark was failing.
So, I put a known good used ignition armature on it. No change, engine still surged.
I liberally sprayed the exposed portion of the intake pipe, and sprayed brake cleaner into the blower housing around the intake pipe. Again, no change in the surging.
Now, with the engine good and warmed up, if I hold the throttle, the engine speed seems to settle out. I say seems because, by ear the engine sounds better, but I am unable to get a stable reading on my TA100 SmartTach. The reading cycles from 1500 to 4100rpm. The engine does not sound like it is surging when I hold the throttle.
So, I am running out of ideas...
Seth K. Pyle
1. Check flywheel key
2. New plug (just for the heck of it)
3. If it seems to stop surging when holding throttle steady, it's more likely a governor issue - check carb throttle for any sticky points, check throttle shaft for wear (air leak) or any binding in the linkage , worn linkages, or try adjusting the governor to a different RPM setting - lean misfire can make tach jump around a bit, as well. also depending on governor type, check linkages and shafts for even the slightest binding ior stickiness, if mechanical governor, time to pop the crankcase cover and check gear and flyweights as a last resort.