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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 26040
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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18hp riding mower engine: intermittent engine freeze when cranking

Customer Question

18hp riding mower engine: intermittent engine freeze when cranking with startert. Occasionally will start, run smoothly for awhile with lots of white smoke exhaust at first, then stall and stop. The freezing occurs after mower sits for a week - must hand crank to turn over, is hard to crank through full cycle - very hard to manually turn through about 1/2 rotation, then turns freely through a full rotation, then hard again at same point. Seems like a valve that won't open to allow exhaust from cylinder. Any ideas would be appreciated :) - Mike
Submitted: 7 months ago.
Category: Small Engine
Expert:  Curtis B. replied 7 months ago.
when it sits, remove spark plug and spin engine, to see if there is fuel on top of the piston. Sounds like you have carburetor that is leaking and letting fuel get into the cylinder between uses. Be sure and also check the oil and be sure you don;t have gas in the oil. It would be overfull, or thin,or smell of gas!
Expert:  Curtis B. replied 7 months ago.
Did you see my response?
Customer: replied 7 months ago.
Thanks, ***** ***** you were correct with that diagnosis- the cylinder was full of gas. I'm waiting for a replacement carburetor I ordered, as I didn't want to fool with a carb kit. I plan to change the oil along with installing the new carb - I will let you know if the problem is gone. Cheers ***** *****
Expert:  Curtis B. replied 7 months ago.
I like to install an inline fuel shutoff valve in the line from the tank and shut if off between uses. This keeps any leakage from occurring. Briggs 494768 is one . Thanks.
Customer: replied 6 months ago.
Installed new Nikki carb, changed oil to get rid of gas in oil (there was lots of it), and she runs like new! Thanks for the advice, Curtis
Expert:  Curtis B. replied 6 months ago.
Thanks, ***** ***** to close and get me credit.