Jeff Enders 3 #1 Posted April 24 One of my 312-8 garden tractors suddenly lost power. I could hardly get it in the barn. The RPM's just dropped right off. I've checked everything I know how to check, which isn't alot, Ha Ha. But what would make the engine drop right down to below idle? Any suggestion? Share this post Link to post Share on other sites
Ed Kennell 35,943 #2 Posted April 24 Lack of fuel. Fuel tank vent clogged? 3 Share this post Link to post Share on other sites
lynnmor 6,820 #3 Posted April 24 Throttle cable broke or came loose? 2 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,530 #4 Posted April 24 If you have an original muffler as was on my 1990 model 312-8 A baffle in the muffler can burn off and plug the 2nd baffle. The engine will run smooth but not rev up. When it happened to me the baffle fell off it's location when the engine is shut off. Restart and run OK until the floating plug works it's way to the hole in the second baffle again. If you bang the muffler you may hear the floating plug rattle. The inlet tube of the muffler goes through to the far side of the can. The tube is drilled full of small holes for the exhaust to exit and there is a cap on the end of the tube. The tube burns off at the holes leaving the cap and a bit of the tube to float around. 4 Share this post Link to post Share on other sites
Jeff Enders 3 #5 Posted April 24 Thank you for the thoughts, I'm on it. Share this post Link to post Share on other sites
ranger 1,652 #6 Posted April 24 I had the same thing with a big diesel engine. It would start and run at idle all day long, but cut out if revs increased? It had been diagnosed with all manner of reasons why, but then we noticed that the exhaust was very quiet? There was virtually nothing coming out from the tailpipe! The D.P.F had broken up internally, causing a huge restriction. Removing the engine side differential pressure sensor allowed enough gasses to escape and the engine would then rev up. Try putting your hand close to the silencer outlet to see if it feels restricted. If it’s not the exhaust that’s the issue, then as others have said it’s probably a fuel supply problem? 1 Share this post Link to post Share on other sites
tunahead72 2,346 #7 Posted April 25 A massive buildup of carbon in the combustion chamber MIGHT cause the symptoms you're seeing. Have you ever pulled the head to see what it looks like in there? You could start by removing the spark plug and shining a flashlight in the opening to get a clue, maybe clean the plug with a wire brush and set the gap while you're at it. Share this post Link to post Share on other sites
