Leak down Test

[whoitd]

When performing a cylinder leak down test do you have to hold the piston @ tdc that you are testing? I am testing to see if my head gasket are leaking on my 1988 Johnson 150. I have 110 psi in all 6 cylinders, but the gaskets look like they are crusty looking from the outside. Thanks , Jim

 

[RPJS]

Re: Leak down Test

Yes piston at TDC,
With the compresion numbers you have I would be very suprised if you have any problems with your head gaskets.

 

[R.Johnson]

Re: Leak down Test

The piston you are testing should be slightly over TDC, and you block the next piston that is coming up on TDC.