Another dumb question...

[eastonct124]

I know from years of experience, kohlers can take a beating even when worn out….but has anyone ever lost an engine with piston slap when, lets say "throwing some serious snow"? My new 147 (bought for a song) was picked up to make snow work easier than constantly moving the 122 in and out of creeper. But, I noticed when I take off quick at half throttle with little load, the engine knocks hard and blows a big puff of oil smoke. otherwise, not a problem , not even a tick. So I'm assuming piston slap.

[J-Mech]

Sounds like spark knock. I'd pull the head, clean it up and install a new gasket. Then adjust timing and install a new plug, check the points.

It takes a keen ear to know the difference between piston slap, rod knock, and a broken piston skirt, or even spark knock. If you had such a loose bore that the piston had "slap" when warm and under load, it wouldn't have any power either.

[eastonct124]

Thought of that, but the big puff of black smoke makes me think major blowby when the piston is cocked from the slap. I ask because I'm leary of putting the qa42 on it and doing damage. I've been using the 122 for years and it runs great…it's just tedious compared to the ease of a hydro.

[J-Mech]

Black smoke is fuel related, not oil. And if it's spark knocking, you will damage it....... eventually.

[eastonct124]

OK, makes sense. I haven't touched the timing yet…it runs.
The more I think about it….it does have that hard start thing here I have to crank it over, then pull the choke, and the second it fires push it in half way because it's advanced too far so it wants to stop in mid-stroke at compression. It's one of those things I put on the mental list to fix, then the weekend comes and I'm doing all the property stuff, splitting wood and hauling it to the house….then it's dark and I'm beat.
I think you're right…thanks.
-Richard

[Mike McKown]

I had a 14 hp engine act up similar to that. The static timing was okay, it would start good and run good up to about half throttle. After running awhile cutting grass, it would start hammering, blow smoke and quit. It'd start right back up and then repeat. If I let it sit awhile, it would okay for a few minutes and then do the same thing again.

Turned out the point spring was weak and I guess when engine got hot, the spring would lose more tension and would let the points work as intended.

The points that failed were factory installed by Kohler in 1974. The ran 4-5 years without a problem. The second replacement set is still in the engine.

A new set of points fixed it.