plz help mercury sport drive 90hp compression with force block

[Josh122593]

What is piston compression supose to be on a mercury 90 hp sport jet 3 cylinder?I tested it today and it was top-125 middle-100 bottom-120.Greatly appreciate any help.

 

[jim_b_20653]

Re: plz help mercury sport drive 90hp compression with force block

125 is good. What is more inportant is that they should be equal. It sounds like you may have stuck rings. You should decarb, then restest the compression, hopefully the numbers will look a little better.

 

[Josh122593]

Re: plz help mercury sport drive 90hp compression with force block

thanks do u use sea foam to decarb if not what do u use

 

[JB]

Re: plz help mercury sport drive 90hp compression with force block

Duplicate post. See Merc.