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mbrook

Briggs crankcase pressure concerns

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mbrook
The engine is a freshly rebuilt 12hp cast iron Briggs. The problems I have with it are it is very hard to start and I have oil coming out of the carb. I have not noticed any oil burning, but if I mow with it (about 1 hour) the carb will have oil dripping from around the air cleaner. I'm assumming this is from crankcase pressure, but I not sure why.

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Questions: 1. is the crankcase over filled? 2. is the Pcv Assy clean and working 3. are the new rings sealing properly or turned in the right directions? Steps: 1A. check the oil level 2A. Clean the PCV (Positive Crankcase Ventalation) assy and check the hose for good unobstructed condition. 3A. perform a leak down test to check the ring seal @ 90 psi set the position of the piston at bottom dead center with both valves closed if air comes comes out either valve its not a good test if valves are closed and air only comes out of PCV then the new rings are not yet sealed properly. of the cylinder holds the 90 psi with no leakage then your induction system is sucking the oil out of the crankcase witch means the PCV assy is bad and needs replaced. Safety Note: The leak down test can be done at top dead center but is not advised because forcing air into the cylinder will cause the piston to move and the flywheel and crankshaft this can cause a pinch situation and can cause damage to fingers.

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