[lovedssron5]

what should the compression be, and where to look for parts and supplys

[Scaaty]

don't know the year (helps), but anything over 90 and within 10% on all cylinders is good...parts are everywhere

[lovedssron5]

like an auto parts store? I don't know anything about boats I've worked on a couple of car never a boat. I just did my first fiberglass patch the other day looks good now let see if it holds.

[diaric]

merc dealers if newer, online stores and aftermarket dealers if older. depends on year and location. napa does have some stuff

[lovedssron5]

I have all older stuff 1954 mercury mark 58a, 1965 mercury 90,
1953 evinrude 25 big twin. and a 70's johnson 25 just got it. the only one I have that actully runs is the 1954 mercury mark 58a once it's running I dont have a problem keeping it up it getting them running thats my problem

[diaric]

try here http://www.oldmercs.com/mark58a.html

[lovedssron5]

I don't know if someone put the 58a cover on it or painted the 55e looks ID. thats very close to the same thank you!
I really looking for all the help I can get with this mercury 90

[lovedssron5]

compression test
1:90
2:100
3:110
4:90
5:110
6:100
is this a good test or bad

[diaric]

its not bad, but its not great. the 2 at 90 are a big spread from 110. rings could be a little sticky and a decarb might bring them all up a bit .
http://forums.iboats.com/showthread.php?t=158076