low compression

89skeet

Recruit
Joined
Mar 12, 2008
Messages
2
I have a 89 skeeter with a 70 hp mercury on it. The compression is as follows: #1-100, #2-120, #3-90. Would this motor be worthy of a rebuild. I might attempt this myself (average joe-not a mechanic). Any ideas what cause this to happen?? Do I need to buy a new or used motor? I'm fairly new to the boating world and this boat will satisfy until I get more experience on the water and try to buy a real nice boat.Please help.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: low compression

Howdy, skeet.

Welcome to iboats. :)

Sounds like carbon buildup to me.

Do a thorough decarb, then do the compression test again.
 

Windykid

Lieutenant Junior Grade
Joined
Apr 17, 2007
Messages
1,177
Re: low compression

Welcome skeet!

I agree with JB, get some seafoam from the auto parts store and do a decarb, it should loosen up the rings and increase compression.;)
 

gss036

Commander
Joined
Jan 18, 2003
Messages
2,914
Re: low compression

Get the SeaFoam DEEPCREEP along w/regular SeaFoam. Remove move the plugs and spray it heavy w/the deep creep and let it soak overnight and the fire it up and repeat again w/SeaFoam deepcreep and run w/fuel SeaFoam mixture.
 

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: low compression

Decarbon it.
If that fixes it, they were right and you're in fat city.
If the compression remains low in the one cylinder, you're lookin' at an overhaul.

hope it helps
John
 

89skeet

Recruit
Joined
Mar 12, 2008
Messages
2
Re: low compression

thanks for all your replies. I'll give that a shot and see what happens. Maybe the boat shop just wanted to sell me a NEW boat.
 
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