Shit breaks...

**roadhog0** · 01-21-11, 07:03 PM

Well, I got this big ol' sears tractor (1973 ST12) that I've had for a while and love because the thing is a straight up work horse! Ive had minimal problems with it since the day I got it. And since it's a Tecumseh engine the rule applies, runs well forever but when it has problems its a pain in the ass to figure out. I went out last weekend and tried to start it up and nothing, wouldn't start. Awesome.... Go to work on it today and try to start it, thing starts trying to run out the INTAKE!! Blue flames shooting at the carb and all! So WTF happened here im wondering. I've checked everything I can without opening the crankcase and im hoping that it didnt break the machined timing gear.... So I love when my shit breaks. Im happy it didnt break in the middle of mowing season though!

**deathgodusmc** · 01-21-11, 10:15 PM

Im not much on small engine repair but i can say when that is happening to any other engine it means the timing is way out. If it has a chain i would check if it slipped. The reason i say that is typically when the timing is off it will try to fire with either the intake or exhaust valve open. Your particular scenario would be a intake valve not shut.

**roadhog0** · 01-21-11, 11:20 PM

Whats silly is the intake isn't shut. I'm pretty sure ive narrowed it down to a broken sheer pin on the cam gear but I dont want to open the crank case :P But I got a small rock in the cylinder somehow and I think it jammed the valve... So I think it sheered the pin on the cam gear :/

**deathgodusmc** · 01-22-11, 01:00 PM

That would definitely do it. On the good side sheers pins are cheap but you have to find a gasket kit for that thing and i have to say dont think thats going to be an easy one to find. I've had that issue in the past and it sucks making gaskets. The problem with opening an old engine to fix one issue is that you end up with more shortly after. Many years ago i could break those down and put them back together in 3 or 4 hours but its been 20 something years since then. I would recommend just rebuilding it or replacing it with a new engine.

**roadhog0** · 01-22-11, 11:35 PM

Well I've rebuilt it myself once and gaskets and parts are still fairly easy to find which is good. I lucked out and found out the problems was the spark plug. Dont know how or why but it was the plug. The down side is I had it running for 10 minutes and the coil(Alternator) shorted out... So i'm fixing that right now and then reinstalling it...