1985 85 force compression

cards

Cadet
Joined
Aug 11, 2003
Messages
7
Did compression check 1st 120 2nd 100 3rd 90. Last year did check they were all within 5. What would cause this and will a ring job fix it or is it more involved? How much would a shop charge to fix the problem? Or is it something you can do yourself and how much are parts? Or should i junk it and start new. New to boating thats why so many questions. THANX
 

The Marine Doctor

Commander
Joined
Jul 25, 2003
Messages
2,177
Re: 1985 85 force compression

You can start yourself by removing the head and checking for a blown head gasket.<br /><br />Hopefully this is the problem.<br /><br />TMD
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,754
Re: 1985 85 force compression

Do a thorough decarb of your engine. You may just have some stuck rings. Do this before the break!<br />Hopefully you can free them up and get the compression back.<br /><br />Your intent is REMOVE the existing carbon buildup from the cylinders, heads, and rings, a spray decarb solvent product, such as SeaFoam Deep Creep, is needed. Some people use one can per cylinder.<br /><br />Run engine at fast idle, with engine running, slowly spray liberal amount into each carb, its gonna smoke up the place,<br />spray for a couple minutes, now spray a larger amount into carbs until engine chokes out and stops.<br /><br />Remove spark plugs and spray decarb liberally into each cylinder, install the spark plugs, let it soak for 1 to 6 hours. <br /><br />Start the engine and run at medium throttle, or if at the lake, run it at full throttle. It won't hurt to spray some more through the carbs. Run it for atleast 10 minutes to flush the crud out of your engine. Now remove and clean, or replace the spark plugs. <br /><br />It works well to do the spraying, the night before you go to the lake. This way you can let it soak overnight, and really flush it out at the lake.<br /><br />Don't do this in front of the garage door or the house, unless you want it coated with greasy crud.<br /><br />If you get tons of crud out, you may want to do it a second time.
 
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