1987 Mercury 70hp EFI - White Smoke after running

CTSurfrider

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May 25, 2015
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2
Good evening,

I've had the subject engine for about a year now. After cleaning out the carb and fuel system last year she was running great when I put her to bed last fall. She started up fine this morning and ran great but when coming back down to an idle there was a good amount of white smoke coming out of the exhaust. The engine was pumping plenty of water through the hose but not out the exhaust. I don't recall if this engine also pumps water out of the exhaust. When I ran her this afternoon I had the same issue. Little to no smoke during idle, ran up the engine and it ran great, but then had white smoke again when bringing it back down to idle. The white smoke slowly subsided over time. I'm worried it may be overheating but friends seems to think it's an oil injection issue. Unfortunately the alarm is not working so I'm left to other diagnostics. Any suggestions would be appreciated. Thanks in advance.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
White smoke is water in the combustion chamber, blue oil, black unburned fuel. Pitted cylinder? You didn't give many clues as to just what it is we are supposed to guess on. EFI stands for Electronic (controlled vs mechanical) Fuel Injection. You don't have carbs with fuel injectors. I think you meant to say VRO type oiling (Variable Ratio Oiling) which varies from 80:1 at idle to 50:1 at WOT.
 
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CTSurfrider

Recruit
Joined
May 25, 2015
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I meant to say oil injected vs. EFI, sorry for the confusion. Unfortunately the only clue I have right now is the white smoke because the engine ran great and there are no other issues. After reading some other posts I'm going to pull the spark plugs to see what their condition is.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
I meant to say oil injected vs. EFI, sorry for the confusion. Unfortunately the only clue I have right now is the white smoke because the engine ran great and there are no other issues. After reading some other posts I'm going to pull the spark plugs to see what their condition is.
Cool day with high humidity and cold engine can do it normally, no big deal.
 
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