QuestionI have a rototiller with a 3.5 hp B&S motor. According to the serial# it is a 1975. The motor starts easy and runs great for about 10 minutes and then it dies. It has to cool down to start again, usually 1 or 2 hours later. It has a new plug and points. The carb has not been touched.
Help please!
AnswerHi James,
Sorry for my delay. The holiday was busy here and set me back.
You will need to determine if the problem is a lack of spark or a lack of fuel flow. Right after it quits, remove the spark plug, reconnect the wire and lay it against the engine head. Pull the engine over and watch for spark at the plug's electrode. If no spark and the switch and wiring is correct to the coil, replace the coil.
If good, then try to start it while squirting fuel or starting fluid into the carb intake. If it starts and you can keep it running by adding fuel, then the carb most likely has dirt, debris or gummed fuel inside.
You will need to remove the carb, disassemble it, clean all the small internal openings and blow it out with compressed air. Probe each and every hole with a small wire. A carb rebuild kit wouldn't hurt either.
Another possibility if the problem is fuel related: Check the gas cap to make sure it is venting and not causing a vacuum in the tank.
Let me know how you make out.
Michael
