new compression

[uncwillie]

With my new compression tester i read 35 psi in the lower cyl. and 60 in the upper, on my old 8 hp Evinrude. A shot of lube oil into the cylinders, with the pistons facing skyward brought the lower up to 55 and the upper to 100 psi. Another similar motor has 80 psi in both cylinders, though i have not tried the oil trick on it yet. Ideas? Guess i better get out the torch for engine #1, eh?

 

[Barnacle_Bill]

Re: new compression

Time to rebuild.

 

[OBJ]

Re: new compression

Jim....sounds like ya' got some light scoring or scuffing in the cylinders. Pull the head and take a look see. If it's a late model...may be worth saving.

 

[JB]

Re: new compression

What Bill said, almost.<br /><br />Not only is your compression low, the spread is almost 50%.<br /><br />I would try to decarb it. It is possibly choked with carbon.<br /><br />The other engine sounds pretty good (both cylinders the same), but I would decarb it, too.<br /><br />Good luck.