Uneven piston gap to Cylinder walls
Posted: Wed Jan 16, 2019 9:34 pm
Hi Guys,
Just started working on my new Model 70 with Kohler K161S 7hp I got a in December. I took the carb off to clean / repair it, it showed a low of wear in the hole on the Governor linkage, but more concerning was that one of the throttle plate screws was missing, Must have been a long time before it was put away because the throttle
plate was loose and there was wear where the plate had vibrated against the carb. throat.
Took the head off today to see if the screw cause foreign object damage to the valves at it passed through the engine. Fortunately the valves showed no damage from the brass screw, however I noted that the piston to wall gap was larger for about 30 degree near the exhaust valve. When I cleaned away the carbon I can see the top ring is making good contact on the wall. It just appears to be from the top ring on up?
Is this common on high time engines? Perhaps piston wobble from skirt wear. I do not see any scoring on the cylinder walls, I notice a , 0.010 on the top of the piston top. I can put it back together and see what happens or change a piston and rings while I am this far.
Appreciate the benefit of your experiences
Dick Cupka
Just started working on my new Model 70 with Kohler K161S 7hp I got a in December. I took the carb off to clean / repair it, it showed a low of wear in the hole on the Governor linkage, but more concerning was that one of the throttle plate screws was missing, Must have been a long time before it was put away because the throttle
plate was loose and there was wear where the plate had vibrated against the carb. throat.
Took the head off today to see if the screw cause foreign object damage to the valves at it passed through the engine. Fortunately the valves showed no damage from the brass screw, however I noted that the piston to wall gap was larger for about 30 degree near the exhaust valve. When I cleaned away the carbon I can see the top ring is making good contact on the wall. It just appears to be from the top ring on up?
Is this common on high time engines? Perhaps piston wobble from skirt wear. I do not see any scoring on the cylinder walls, I notice a , 0.010 on the top of the piston top. I can put it back together and see what happens or change a piston and rings while I am this far.
Appreciate the benefit of your experiences
Dick Cupka