Re: Lower unit pressure/vacuum Test

[fleetwin]

Well, recommendations from OMC have changed over the years. The thing to remember is to use low pressure/vacuum such as 3-6PSI to test seals. Using the higher pressure/vacuum (16-18PSI) can help marginal seals seal up better. It is best to submerge the gearcase in a bucket of water when pressure testing, be sure to turn shafts and move shift rods while in the water to help isolate leakage areas. The higher pressure/vacuum settings are used to test gaskets/orings. I hesitate to recommend doing the vacuum tests on gearcases with single lip seals, the vacuum might overcome the seal lip, pulling air past it, showing a "leak". In any event, don’t submerge the gearcase in water for vacuum tests, you won’t be able to see leaks and water will be pulled into the gearcase. I would say that 10-15 minutes is adequate for holding a particular pressure/vacuum reading. Keep in mind that faulty equipment/leaky hoses are often to blame for leakage problems, don’t drive yourself crazy (like I have done) trying to fix a gearcase leak when it is the tester that is leaking!