compression on an Evinrude 150 horse--Advice?

[Fraziermotorsports]

Looking at a boat with a 1988 Evinrude 150 horse V6 on it. I checked the compression, and I got this---

100#
110#
120#
100#
108#
120#


Do those numbers seem ok? The cylinders vary more than the 10% i've been told they have to be from each other-- but its close.

Also, does 100 lbs of compression seem a bit low? My chrysler 80 horse pumps 145 lbs all day. Seems a tad weak.

Thanks!

 

[jonesg]

Re: compression on an Evinrude 150 horse--Advice?

The big V6's run lower compression, mine are around 85-90.
Mine runs good.

A seafoam treatment might very well even things out for you.
How does it run anyway?

 

[tashasdaddy]

Re: compression on an Evinrude 150 horse--Advice?

suggest decarb
Decarb, take a can of seafoam put 3/4 of it in the gas tank, with only 1 gallon of premixed gas. put the rest in a spray bottle. start the engine, and let it come up to temperature. then remove plugs, and them some real good shot of seafoam into the cylinders, replace plugs, let sit 15 minutes. restart, and spray the rest of the seafoam into the carbs, so the the motor almost stalls, wait and repeat until the seafoam is gone.then take for a wide open spin. then put in new plugs, ad premixed gas to the tank, and take it for a wide open throttle spin. it is going to smoke like a house on fire, during this process.

afterwards compression.recheck

 

[Fraziermotorsports]

Re: compression on an Evinrude 150 horse--Advice?

Thanks for the advice Jones and Tashdaddy (sp)-

I've used the seafoam on my other outboards-- it works great. I just wanted to see if you guys thought those numbers looked ok.

Motor runs good--

Thanks for the advice!!