Please help with craftsman rider bent intake rod

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  #1  
Old 05-24-14, 01:59 PM
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Please help with craftsman rider bent intake rod

I have a briggs and Stratton 20 hp engine 31P977-0575-E1 OHV on a craftaman rider. Just bought from somebody claimed only 40 hours or so on engine and has sat for few years. First time mowing with it there was some white smoke coming from exhaust not too bad figured it would clear up with more driving. This time finished lawn seemed to be smoking more just about got it put away and it began sounding like it was backfiring loudly would not restart let it sit for a while and tried again did not want to turn over much seemed like too much compression. Pulled plug cranked for 10 seconds or so and put it back tried again still same problem cranked then stopped like it was getting full of compression. pulled bolt on flywheel to check flywheel key it is fine. pulled head looks like new head gasket cant see any problems with it. Piston and cylinder full of oil and carbon build up intake rod is bent. Should I replace intake rod and try again or does engine need more work. How is the oil in the cylinder and what steps should I take from here? Thanks for any help.
 
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Old 05-24-14, 04:08 PM
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The intake rod (assuming the pushrod for the valve rocker) should be replaced. It was bent when the intake valve was hydro locked against the oil in the cylinder. The oil was why the cylinder seemed full of compression.

With the rod back in place, the oil out of the cylinder, and the valve clearances set the only question on the way to a fix is why the oil was in the cylinder.

A common problem with a mower that sat for a long time is the float sticking which allows gas to fill the crankcase and thin the oil. That over fill can blow up into the cylinder. Check the oil for overfill and smell of gas. If any at all, replace the crankcase oil, double check the level and make sure the float is shutting off the flow of fuel. Then run it and see how it does.
 
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Old 05-25-14, 06:30 AM
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Thanks marbobj one question I have is can I turn the flywheel with the head off and move the piston to tdc to clean it with out causing any problems such as timing? thanks for the help I going to replace the rod check out the carb hopefully the parts store will be open on Monday.
 
  #4  
Old 05-25-14, 04:55 PM
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That wouldn't affect the timing. When you reassemble it put the push rods in last. There is a little cam rider pocket for the lower end of the rod to sit in. The upper end goes in the valve rocker. Double check that fit on both ends as you adjust the valve clearance.

Were any of the head bolts loose or did the gasket show any signs of blowby? If the gasket was new there may have been an installation problem that contributed to the oil in the cylinder.
 
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