QuestionQUESTION: I have a 9hp vertical powerbuilt B&S(model #28b702,type 1.154-E1 that seems to be (hunting) idles up and down.I've checked the gas,air filter,fuel line,new muffler,new spark plug,changed coil & set correct gap to flywheel,cleaned breather assy,tryed another working carb,and tryed to adjust the govenor.Could there be buildup on the valves or possibly a damaged governor gear inside the engine.Sometimes seems to be popping back thru muffler as well.Any suggestions?
ANSWER: I think I'd try cleaning the head and chamber. Just pull the head and clean all the carbon off. I'd use a new head gasket putting it back together. Sometimes the governors stick, especially if the oil hasn't been changed regular or the engine has been overheated. And there could be an internal problem with the governor. So far you've made the right moves and just need to keep going deeper. Thanks, PK.
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QUESTION: I mowed the yard today and the mower ran fine with the blades running and mowing.After finished I turned the blades off & started down the driveway then the problem started again! Under no load the problem came back.Governor?
AnswerThere's really no way for me to say without being able to physically inspect the machine. If the crankcase is gunked up enough, the governor may not be working properly. If it were broken, I would expect the problem to be constant. Cleaning the head is standard maintenance on L-head engines, we recommend doing it every 100 hours, so I'd still do that.
A sticky governor might cause loading up and that would cause some backfiring through the exhaust. A badly carboned combustion chamber can cause erratic behaviour as there may be excessive quench during combustion. Thanks, PK.
