ORIGINAL: Artisan
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When running crankcase pressure, a one way valve must be used, otherwise the end result is no pressure at all, since the piston goes up and down, causing the pressure to swing from positive to negative to positive over and over again.
Crankcase pressure should not be used unless a pressure regulator is employed at the carburetor.
Timed pressure can be obtained by tapping the crankcase under the rotary valve window that is cut into the crankshaft. Again, this should not be used without a regulator of some time to prevent flooding the engine.
nope, case pressure doesn't need a check valve to work. in fact, at idle it will still make enough pressure to flood an engine.
OLD and CHEAP K&B outboard mod for making power: carve away the muffler portion of the outboard under the engine and install an exhaust throttle, chuck the carb and put a neele valve through the carb screw holes and finally, put a pressure tap in the case to feed the tank....works with plane engines too!
dave