dano Posted May 22, 2006 Posted May 22, 2006 Was mowing the lawn today with my Sunstar and the motor (20 HP Mag.) started missing and lost power. Finally it quit altogether. While trying to get it started, it was smoking like a Steam locomotive, lots of white smoke coming out the exhaust. After sitting for about 15 mins., it started up again, with no smoke. Anyone have any idea what might the problem might be?
sandyhillbill Posted May 22, 2006 Posted May 22, 2006 Had mine do this several years ago. Ended up finding that the rod cap came off one piston and broke that rod and the motor never stopped running. You can easily check this by pulling the plug wires one at a time. It will either quit or continue to run.
comet66 Posted May 23, 2006 Posted May 23, 2006 Ignition module breaking down under heat could cause similar problems. Although I've never had one of these engines overheat on me, I can see where this might give you a similar condition. I do know that every time I pull the shrouds off of mine I am surprised at the amount of debris that collects inside them.
swede Posted May 23, 2006 Posted May 23, 2006 Check your oil to see if there is gas in it. I saw this before on a friend's mower where the carb float needle was not seating and flooded the crankcase. His mower acted the same as yours. Also, make sure the breather is clean and working.
SteveP Posted May 23, 2006 Posted May 23, 2006 After reading about breathers on these M20's I checked mine. It's not much more than a rubber diaphragm. Completely tore off. Hopefully this reduces my oil consumption. Everyone should check theirs.
swede Posted May 23, 2006 Posted May 23, 2006 That must have been a common problem with these engines since you can't get that rubber diaphram anymore. Now the replacement is a whole new lower plate that has a thin metal strip that acts as the valve.
dano Posted May 23, 2006 Author Posted May 23, 2006 Up-date on my Sunstar: I followed Swede & Sandyhillbill's advice and ultimately found that there is gas inside the carberator float. The rubber plug in the breather seems in good shape, and there is a rectangular element inside the breather that is oily, I assume that is normal. I'll try a carb rebuild and see if that fixes the problem.
Recommended Posts