fuel in oil after carb rebuild

Toonster

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Mar 21, 2009
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Hi, I have a used pontoon with a 2000 Mercury 60HP 4stroke BF that is getting fuel in the oil sump after rebuilding the carbs. Following the Carb rebuild FAQ and other posts, the carbs were rebuilt with rebuild kits; the engine starts up and revs just fine. Only problem is this making fuel issue that I think is a flooding issue based on the 4Stroke "Making Oil" by Willy B. Wright post. I've pulled the card off several times and verified that the auto enricher is not stuck, the floats are level with the carb body, and the needle is seating by inverting the carb and blowing into the fuel inlet. Being a newbie with boats and engine, I am stuck after reading numerous posts and is appreciative of all responses. BTW, the rebuilt carb makes lots of oil within a day of tuning, and the engine still idles after all idle mixture screws are seated.
 

Toonster

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Mar 21, 2009
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Re: fuel in oil after carb rebuild

Well, I replaced the floats and it still making oil. :confused: Could it be the auto enricher? I connected to a 12V battery and it does seem to be working.
 

JB

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Re: fuel in oil after carb rebuild

It seems to be getting fuel when you are trying to deny it fuel (idles with all idle screws seated). First suspect: improperly seating idle mix screws.

I would also question the T'stat.
 

Toonster

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Mar 21, 2009
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Re: fuel in oil after carb rebuild

JB - Thank you for your response. Does the T'stat controll the auto-enricher so that a bad t'stat will signal the enricher to open and flood the engine? Is my question even correct? :redface:
 

Toonster

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Re: fuel in oil after carb rebuild

Well, I found the problem; turns out to be with the fuel pump diaphram. Replaced it, and it's not making oil anymore. Though the plugs are all wet now and engine dies whenever I go from WOT to idle. New pump overpowering the carbs?
 
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