Compression Loss Prevention?

F

Fly-GTI

Recruit
Joined
Jun 26, 2001
Messages
2
Hi Everyone,<br /><br />I'm a newbie, this seems like a good board, so I'd like to ask ya'll a question about my new motor.<br /><br />I just bought a 15' Bonito with a '86 70 Horse Johnson outboard. Before buying I ran a compression test and came up with the top cylinder @ 110 PSI and the bottom two cylinders @ 125 PSI.<br /><br />[bold]How can I prevent any more Compression Loss in the top cylinder?[/bold]<br /><br />Thanks!<br /><br />Alex<br /><br />------------------<br />Watertoy - 15' Bonito<br />Roadtoy - '01 VW GTI
 
JB

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Compression Loss Prevention?

Hey, Fly GTI. Experts will disagree with me and with each other, here.<br />1. Avoid premium gas and gas with alcohol in it.<br />2. Use only the best oil you can get. A best buy is WalMart Super Tech TWC-3 rated.<br />3. Avoid fuel additives and spray-into-the-carb "decarbonizing" elixers.<br />4. Avoid operating at very low speed for extended periods.<br />5. Follow preventive maintenance procedures recommended in your owner's manual (If you don't have one, get one now.) as though your life depended on it.<br /><br />You may have a mechanical failure causing the drop in compression, or it may be "gunk" causing the rings to stick. Check with your OMC dealer about a Service Bulletin to reroute cooling water in 3 cylinder engines.<br /><br />Red sky at night....<br />JB
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12Footer

12Footer

Fleet Admiral
Joined
Mar 25, 2001
Messages
8,217
Re: Compression Loss Prevention?

No argument here with JB, except for #3 (but then ,he knows how much I swear by the spray decarbon cleaners). But that's another thread
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F

Fly-GTI

Recruit
Joined
Jun 26, 2001
Messages
2
Re: Compression Loss Prevention?

Thanks guys! I really appreciate your help.<br /><br />Any suggestions on where to get an owner's manual for this motor?
 
S

sony2001

Chief Petty Officer
Joined
Mar 17, 2001
Messages
607
Re: Compression Loss Prevention?

Fly-GTI A small effort to prevent further loss of compression could bring it back up. I would run it ,enjoy the summer, every 10 hrs pull the plug on a warm engine, spray the piston head with a decarbonizer and start it up 15 minutes later. Check it [psi] in the fall.<br /><br />------------------
 
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