QuestionQUESTION: Cant keep Lawnboy 195cc 4 cycle push mower model# 10684 TECUMSEH MOTOR running. It runs about 5 minutes and then revs up and down finally stalling out. where do i go I changed plug and it still does it. Any ideas what to do?
ANSWER: It could be just some junk in your carb, remove the little nut on the bottom of the carb and see what comes dribbling out, let it dribble on the deck a little, and clean the tiny holes in the nut, and reinstall and try it. Run it a while, and if starts stalling again, try loosening the gas cap, it may not be venting either.
If the problem still persists, then we could possible have a valve
problem, or ignition.
---------- FOLLOW-UP ----------
QUESTION: I opened nut on bottom of carb and clean gas dribbled out. i took carb apart and everything looks like new. then put it all back together with same results loosened gas cap motor revs up and down then shuts off. what can i look for next?
Answer When these small engines get overheated, the block will warp slightly, and the "valves" that seal off the compression migrate
closer to their lifters, and when they do that, the lifter/valve
clearence is too close, and when the engine/valves heat up-expand,
they cannot seat/seal, compression is lost, the engine dies, restarts
when it cools, etc....
Just "adjusting" the valves is not a real good repair, as the valve seats are thus slightly warped/cocked, and will continue to leak/overheat, but it will likely get you back in the game.
But on this engine, adjusting the valves requires removing them and
grinding them shorter, which will involve a few tools that you likely
won't want to buy. Or not.....
Local shops may or may not handle the problem correctly either,
most shops just grind the seats and "lap" the valves, a correct method would require cutting the seats and valves, but finding a shop that does that is very rare.
But all in all, just adjusting the valve specs would get you going.
