Leak testing your exhaust manifolds
Leak testing your stock exhaust manifolds is just as important as making sure your pipes are leak free. Any time you are rebuilding a ski or if you are having performance problems, you need to check your exhaust manifolds to make sure they don't have any leaks.
Equipment needed:
- Air pump with pressure gauge and 3/8 ID hose (click here for picture)
- Rubber hose caps (click here for picture)
- Exhaust manifold rubber block off gasket (click here for picture)
Procedure
The best time to perform this test is when you have the engine removed from the hull and are performing a leak down test. In order to perform both a leak down test and an exhaust manifold test you will need to have a rubber block off gasket for the manifolds. Install this gasket between the three cylinders and the three manifolds. Once you have completed your engine leak down test, follow these steps to properly leak test your manifolds:
- Install rubber hose caps on two of the three exhaust manifold cooling nozzles. You will need to leave one nozzle on one of the manifolds free for the air pump.
- Connect the air pump to the available cooling nozzle on the exhaust manifold.
- Pressurize the cooling chambers to ten psi. Realize that while in the leak down test you pressurised the combustion chambers and crankcase of the engine, with the exhaust manifold test, we are pressurising the cooling chambers of both the engine and the manifolds.
- Watch the pressure gauge carefully. If the pressure drops you will need to use a soapy solution to locate the leak. Realize it could be something as simple as a loose cooling hose nozzle or that you dont have the manifold tight enough against the rubber gasket. More serious problems would be internal or external cracks.
- If the manifolds can hold ten psi for three to six minutes then they are free of leaks!