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Hi all..new to forum. Hope someone can help me with a strange problem. I have a Poulan 42"rider with a 17.5 Briggs motor, two years old. When I went to start it it will roll a couple of times then just "binds up" Just grunts. Yet when you pull the plug it will roll all day long! Even pulled the muffler in case it was plugged causing back pressure. Was working fine. Oil is good..battery charged fully.
Any ideas appreciated
Thanks

Remove the valve cover and spark plug. roll engine over by hand until you are 1/4 in past TDC on compression stroke(both valves closed) and check the valve clearances. Should be .003-.005 intake and .005-.007 exhaust. Exhaust should be the top valve. If not within spec adjust accordingly. After adjustment then roll engine over two complete revolutions and recheck valve clearances. Also while turning engine watch valves to see if one of the valves bumps off its seat just before TDC compression. If everything checks out then reistall plug and valve cover and try to start mower.

Thanks for the reply...will try that:smile:

Hi again..adjusted valve clearance to spec..still doing it! Any ideas?
Thanks

Need to re remove the valve cover, and then roll the engine over by hand and what the valves open and close, One of the valves should bump off the seat just before TDC compression stroke, to indicate that the compression release is working. if no bump off, then possibly the compression release isn't working, which will require a camshaft change. If you remove the engine and the bottom of the engine to inspect the camshaft just go ahead and replace the camshaft and save yourself a lot of headaches. Sometimes the flyweight will get sticky and hand up, but can be hard to catch in the failed position. I have seen the weight breakoff, the return spring break, and the weight handup and not return intermittently.

Does the oil smell like theres gas in it? If so remove all spark plugs and crank engine while spark plugs are out. Then change oil and oil filter. Then you have carb issue.

My 42 inch cut poulan had the same problem and what he said about adjusting the exhaust valve is exactly right, I adjusted mine and it starts like a new one every time.