Question about Briggs AND Stratton Intek Briggs & Stratton Vertical Engine 21 HP INTEK OHV 1 x 3-5/32 331877-3036 331977-0001

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Hard hitting on compression stroke when starting

Reg battery wont turn over after hitting compression stroke. put on charger and will start. New 410cca battery. Is there a compression relief valve? If so how to fix. I am old school mec and not up on newer stuff.

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If its the 21 or 20 hp OHV single briggs. Adjust vales to .004. The cam also has a decompression that breaks, Causing hard start. So if valves are adjusted and u still have problem. "Could" be cam, remove bottom cover and inspect cam. new cam about 75 to 100 bucks.

Posted on May 21, 2014

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Most Briggs deco vaves are internal and pretty reliable, the valve clearances are very important, if the exhaust valve clerance is too wide the valve lifter will not work, if there is no adjustment yoy would have to fit a new service valve and re do the clerance by removing material from the valve stem

Posted on Jan 05, 2014


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Briggs 17hp intek overheadvalve on a john deere L100 has developed a hard start hard spin on compression stroke. new battery new starter

hi there

pauly46 here

if engine seems to labour when trying to start as if too much compression ?

try adjusting to in and ex valve clearance to 0.003" inlet and 0.005" ex

inlet valve is the bottom valve, and has a alloy push rod. ex valve is top valve and has steel push rod ( as viewed from the front of the machine with rocker cover off ) )

note rotate engine with plug out to tdc compression stroke , then rotate it down the bore on power stroke by 1/4 inch ( 6.35 mm ) this is the point for setting in / ex valve clearances

manual says 1/4 pst tdc on compression stroke - this eliminates decompressor lift from the setting

cheers hope it hepls

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