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low compression

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wjcap4

Contributing Member
85hp merc sat for 3 years. Compression was good when stored(125) Now at 50psi. Is there anything that can be done without having to tear apart? Thanks Bill
 
Go to Walmart and buy some Seafoam in the automotive section. Squirt a few ounces in each cylinder or more and let it sit for a couple of hours or so. Recheck compression. You may have to repeat a few times.

The rings are probably stuck form sitting so long.

When you get it running mix Seafoam with your fuel/oil mixture for a tank or two to clean the motor out good.
Bill
 
So I have good compression in 2 cylinders at 1:18 each and the other two I have 95 do you think the seafoam thing might be an advantage to me
 
ko4nrbs said:
Go to Walmart and buy some Seafoam in the automotive section. Squirt a few ounces in each cylinder or more and let it sit for a couple of hours or so. Recheck compression. You may have to repeat a few times.

The rings are probably stuck form sitting so long.

When you get it running mix Seafoam with your fuel/oil mixture for a tank or two to clean the motor out good.
Bill
Click to expand...

Better yet on the initial fix, google "decarb". Do that for a quicker result and "then" keep SF in your gas. Decarb is a proven process attested to by some of the biggest guns to ever post on this forum!
 
89. 90 horse Johnson vro. I also have a little oil seeping from the upper part of the engine from somewhere that runs down the side of the lower end
 
Willie23 said:
89. 90 horse Johnson vro. I also have a little oil seeping from the upper part of the engine from somewhere that runs down the side of the lower end
Click to expand...

If I understand you, you have a little oil coming from the midsection or lower unit. 2 stroke engines burn oil with their gas. Oily residue becomes part of the exhaust along with the exhausted engine cooling water, both dumping into the mid section and running down to the drain holes and prop exhaust. If it's a small amount and seems to include water droplets, that's normal drainage for a 2 stroker.
 
Start your own thread instead of posting on a 10 yr old one. The title is for a mercury 85 hp and your motor is a Johnson 90 you are not even in the right forum
 
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