1990 Johnson 60 compression-is this ok? Seems a bit odd.

[Nos4r2]

140,130,125. Tested by a marina.<br /><br />It's close to the 10% tolerance-but what's worrying me is as far as I know they weren't supposed to have 140psi compression-did a search on here and a guy from Sweden said the specs were for 120psi NEW...<br /><br />Could this mean the mechanic was an idiot?

 

[OBJ]

Re: 1990 Johnson 60 compression-is this ok? Seems a bit odd.

There is no real "comprssion specks" on them. The OEM service manual don't give them. They do say that the cylinders should be within 10% of each other and 10 > 15% is accepted in the real world.<br /><br />The good thing about your compression is that all the cylinders are above 100. I would venture to say that if you ran the engine, give it a decarb job, the compression would be a little more equal....just what kind of numbers you would see, I couldnt tell.

 

[Nos4r2]

Re: 1990 Johnson 60 compression-is this ok? Seems a bit odd.

That sound promising-many thanks OBJ. I'm looking to buy this motor and I was a bit worried by those figures.

 

[rodbolt]

Re: 1990 Johnson 60 compression-is this ok? Seems a bit odd.

if you suspect any cylinder sealing issues have a cyl leakdown test performed, takes 10 min and is far more accurate than a compression test.