cylinder leakage test

[ferg57]

first of all i would like to thank every one for there input on my last posted question. would someone tell or direct me - on what to do & look for when preforming a cylinder leak test. i have made the equipment to do it. would just like to know the procedure,an what to look for be it good or bad. any help would be greatly appreciated.

 

[Racer]

Re: cylinder leakage test

Well I have never done this on an outboard, but I am guessing the procedure is the same as on a racing engine.

Put the piston at TDC. You will want to put 100psi into the cylinder. If your setup uses 2 gauges, the first gauge should go to 100psi and the 2nd gauge will be lower. Subtract the 2 and you will have your % of leakage.

If you only have 1 gauge, set it at 100psi and then plug it into the cylinder. Subtract the reading and you will have your leakage.

As far as how much is too much, I can not say for sure. On a race engine 20% is way too much but the engine will still run decent. On an outboard I would say if its over 40% then you have a problem for sure.

Hope that helps, if anyone else has something to add or correct, feel free.