QuestionQUESTION: It's a 17.5 OHV tecumseh, runs fine warm but when cold about the only way I can get it to start is pulling the plug wire to the point of barely hanging on, sometimes this works others, not. Have changed plug in the past but not recently, not sure which plug is best.
ANSWER: What brand of spark plug are you using? Is the fuel fresh, less than 30 days old? When was the last time the carburetor was cleaned?
Is the end of the spark plug wire loose? Sometimes engine manufactures will crimp the spark plug connector to the end of the spark plug wire. Maybe when you remove the spark plug wire you are causing a loose connection to work.
Can you send me the engine model and type code?
Eric
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QUESTION: Plug is NGK R BR7ES, new, clean fuel & filter, engine is OHV17.5 Model & type ? this is what I've got, 204803A (H) Family WTPXS 4902A Dis490. It may be a bad plug wire however, once I have it running I can push it back on the plug and it runs fine, starts too when it is warm. Moving the wire doesn't seem to matter as far as shorting out. I have used a plug R4nc and the Autolite equivalent. Carb has never been cleaned, always treat the gas before storing for winter. Again it runs great once started and warmed.
ANSWER: Good call on the fuel treatment. Always use fuel Stabilizer...we use it in our fuel year round and I use year round in my personal equipment to make sure the fuel does not go stale.
NGK are great spark plugs. Is the end of the spark plug, the end that the spark plug connects to, threaded? If so, make sure the tip is tight.
Here is the link for Tecumseh engine information, model and type number:
http://www.tecumsehpower.com/CustomerService/ModelNumberSpec.pdf
Has you engine always had this problem or did the problem just recently happen?
What is the spark plug gap?
To start trouble shooting the root cause of the problem we need to identify it the problem is ignition related, fuel related or something else. The fact that you can pull the spark plug wire to get it to start puzzles me. Once the engine is warm, will it re-start every time?
Eric
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QUESTION: OK, I got a tool to check for spark or current while the engine is turning, it's there, how strong I don't know. Plug gap is .035, and I have had this problem for the last year or more. However, your question got me to thinking, I replaced the fuel bowl two years ago on advice that it was the problem, I also "adjusted" the carb. Now I am wondering if I screwed up the fuel mixture and pulling the plug wire is part of the solution (albeit wrong) to getting it started. I know of only one screw to "adjust" on the carb and with it idling, as I screw it in, the idle goes up. Just where do I need to set this? Also, do you have any other ideas, still starts with loose plug wire when cold, once warm all is OK. Runs smooth, starts right up as long as I don't let it cool completey. Thanks Harry
AnswerTry setting the spark plug gap to .030 inches. The link below is not for your engine but the carb adjustment procedure is the same on single L head cylinders and OHV engines.
Most likely, the only adjustment on your engine is the idle speed screw. Almost all late model carburetors are non-adjustable by design.
Any luck locating the engine model number? It should start with OHVxxxx and then the spec number will follow.
I'm very curious as to why the mower will start with the spark plug wire loose. Try the 0.030 inch spark plug gap and let me know if that helps.
Eric
