QuestionI purchased an MTD 400 rear tine tiller early 09. It has worked great up until today. Pull after pull the only way to get it to fire was with starter fluid. Step 1 - pulled the gas line - no clog. Step 2 - removed the bolt on the side of the bowl - sludge came out. Step 3 - removed carb and cleaned by spraying WD40 through the obvious ports and scrubbed bowl with scotch brite / gas. I feel that I cleaned the unit well. Step 4 - still not able to crank without starter fluid, drained tank and bowl, introduced new gas. I am still unable to get the motor to fire without starter fluid. With starter fluid the motor will crank, and for a brief time I have kept it running with starter fluid. Now I am lost; did I not clean something thoroughly, is the ethanol additive a culprit, could I have purchase more inefficient gas today, is there some part that may need specific attention?
AnswerSince is starts on starting fluid then all systems are functioning except for fuel delivery, aka, the carburetor.
Scotch brite works well to remove the gunk but spray can carb cleaner and an air compressor are necessary to clean the carb. Blow compressed air through all the carb orfices, then carb cleaner, then compressed air again. Late model carbs, like yours, are tuned very precisely to reduce emmissions and thus are very sensitive to dirt/debris. Set the air compressor output to about 40 psi and blow out all the orfices.
To prevent future problems use a fuel stabilizer such as Stabil or other similar brand. This will keep the fuel fresh. Add the fuel stabilzer to your main gas can then you know you fuel will be good up to a year.
Clean the carb be the steps above and let me know if solves your problem.
Eric
