small problem, - B & S timing info needed

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slag

Lifer
Dec 14, 2000
10,473
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I'm working on a 140 CC 500ex briggs and Stratton engine that had a crack in the oil pan. I took the pan off to replace the pan and the engine fell over and the governor fell out. When that happened, my timing got all screwed up. I figured I'd have to match the two marks on the crankshaft to the arrow on the camshaft, but its not correct and belches and backfires when pulled to start. I can't seem to find this info on the web anywhere, so, how is the crankshaft and the cam supposed to be configured for this to work correctly?
 

phucheneh

Diamond Member
Jun 30, 2012
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Don't ever make any assumptions with any kind of timing marks. Sometimes stuff seems fairly obvious, then you look it up and it's something like 'align invisible mark with casting flaw.' :D

Put the #1 piston (how many cylinders is this?) at TDC and see what its valves are doing. They should both be closed. If the exhaust is open (or if both are open; dunno if an engine like that uses a lot of valve overlap), your timing is likely 180 out.
 

slag

Lifer
Dec 14, 2000
10,473
81
101
Don't ever make any assumptions with any kind of timing marks. Sometimes stuff seems fairly obvious, then you look it up and it's something like 'align invisible mark with casting flaw.' :D

Put the #1 piston (how many cylinders is this?) at TDC and see what its valves are doing. They should both be closed. If the exhaust is open (or if both are open; dunno if an engine like that uses a lot of valve overlap), your timing is likely 180 out.

Single cylinder. Good call, I'll put it at TDC and align it so that both valves are closed and go from there.
 
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