1981 Evinrude 35hp compression

[merc 18xd]

Hi

I would like to know the compression specs for an 1981 Evinrude 35hp 2-strokes 2 cylinders.

Ands since it's kinda of an old motor what's the lowest compression acceptable.


Thanx in advance.

 

[OBJ]

Re: 1981 Evinrude 35hp compression

Anything above 90psi on both cylinders and within 10 > 15% of each other is considered very good merc. I have had engines run very well on compression in the low 80's and even a little lower on occasion. But the real key is how close they are to each other.

True, when the compression starts getting down below 80, either time for a for a rebuild or new engine.....this in consideration if a good decarbing didn't help and there are no leaks in the head gasket.

 

[DJ]

Re: 1981 Evinrude 35hp compression

Great advice from OBJ.

As stated, the important thing is that they (cylinders) are close to each other.

If you have not done the de-carb process-do it.

It is described in the link below.

I think you'll find the engine is fine, just dirty-inside.

http://forums.iboats.com/bbBoard.cgi?a=viewthread;fid=36;gtid=1035563