QuestionQUESTION: I have a John Deere rider mower with a Intek 18.5hp, Model 31P777 Type 0367E1 engine. Its 2 Yrs old. It has started running ruff. With the engine at idle I can hear and see the engine fire then the engine speeds up/slows down it fires again speeds up/slows down etc etc. As the throttle advances the sequence accelerates and the engine will come to a fast rpm running slightly rough and sluggish on power. i have replaced the spark plug, air cleaner and gas to no effect. I may be crazy but it seems like its only firing half of what it is supposed to. Is that even possible? Any thoughts would be appreciated. Thanks.
ANSWER: Do you notice any smoke during this?..If so is it black?...what did the old spark plug look like, was it black and have the appearance of a rich mixture? Or was the tip white or grayish as to maybe a lean mixture?...has the mower been running ok though the season up to now, or has this been a problem since you started the season with it?...Tom
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QUESTION: No no smoke, the mower has run smooth and just like new up till this problem. Only thing I can think of it did sit for 3/4 weeks between uses, thats normal in winter here in Fla and Ive done it before and The battery was dead. I jumped the mower off to start it and it starts normal now.
The spark plug was clean and didnt seem to need replaced but I did it anyhow. I cant think of any other quirks.
I could attach a pic of the spark plug I think I still have it, tomorrow if you think that would help.
Thanks
AnswerI would have to suspect the Carburetor. Sounds as if the governor is hunting, because it's not receiving the correct fuel mixture. Either some dirt or something may have clogged one of the jets, or is lodged between the needle and seat. But thats only after I checked and replaced the fuel filter, and checked the fuel pump volume....Tom
