Compression differences too bad?

[coin operated]

I have a 1973 Evinrude 115 hp. using JB's method (warming up, pulling all plugs, etc) I get 128 135 120 and 90. Is that too bad to keep using?
The reason I tested it at all is because when I was on the water the other day, at WOT, the motor sounded like it slowed a bit and then it died. I checked my fuel and fuel lines, and didn't see anything. It started up and ran fine to the dock, but I didn't push it back to WOT because I wanted to be sure I made it in. Could this be from the compression? I am sort of a rookie here, but I have replaced the stator, rectifier and power pack on this motor last year. And yes, I changed the impellar, which was harder thatn it should have been, because whoever did it last lost the plastic guide tubes. Any and all advice appreciated.

 

[Monte1961]

Re: Compression differences too bad?

Yes it could be? The only way to verify for sure is to remove head/s and do a visual inside of cylinders. Something you might try is, seafoam. It has been said that it really helps although I have never had a reason to use it! Good luck and post your results!

 

[wilde1j]

Re: Compression differences too bad?

The compression difference you measured would not make any noticeable running difference. I would decarb the motor, in the hopes of stuck rings in the low hole. See under Top Secret Files.

Retest compression after one or two decarbs.