Merc 50 hp Pressure???

[Dirk W]

I took a 1998 50 hp Merc in today to have the engine pressure tested before I buy it. Im totally ignorant on this stuff but here is my question: The top two cylenders were both at 125 cold. However the bottom one was at 105. The mechanic then started the engine and let it warm up for a few minutes. After that he checked the pressure again and all three cylnders were at 125. Is this acceptable and what would cause the difference?? This was the first time the engine was started in about two months and it was cold out today (10 degrees). Any guidance is appreciated.

[Valv]

Dirk, there is no problem with motor.
Reading with motor cold gives you lower results since piston rings don't seal well. You pressure of 125 on all of them is good, it would be bad if difference of pressure between cylinders is more than 10% (eg. top 2 at 125, bottom at 100), then you wold have to go through some troubleshooting (decarbonizing motor, etc.) before con****ing it as a possible rebuild.

I wouldn't worry if I was you.

Val