I have a Briggs 18 hp with ohv. Model # 31H777. Type #0117E1. Flywheel stops on compression stroke. Adjusted valves numerous times at 1/4" past tdc. Took it to shop and they had no luck. Called Briggs and they said the exhaust valve should open a hair during compression release but it looks to me that the intake is the one moving a hair. New battery, ground is good, starter seems ok. It did start bettre the other day with a 10 amp boost from a charger but I have made some other valve adjustments since and now we are back to stalling on the compression stroke with even the 10 amp boost. So is it the intake valve is the one I should be watching for that slight movement or is it the exhaust valve? I suspect I need a new camshaft or my compression release is malfunctioning. Any input woud be appreciated! Thanks!