04 Merc 50hp 4stroke BigFoot EFI - water in oil, locked up

smithtr11

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May 21, 2007
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I bought a 04 pontoon with a 04 Mercury 50HP 4 stroke EFI Bigfoot last week and low and behold on the second trip out we are running across the lake and start loosing power so i shut it down, i check the oil and it is white. I try to turn the engine over and nothing.

After returning it to the dealer where i bought it, they say they are going to tear into it and figure out what's wrong and fix it. They said that the motor probably isn't hurt and the reason it won't turn over is water doesn't compress like oil and that likely caused it to "lock up". They say it is most likely a blown head gasket. Does anyone know of issues like this with 4-strokes? Are they trying to pull one over by telling me it likely isn't hurt? Any advice would be greatly appericiated.
 

tashasdaddy

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Nov 11, 2005
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51,019
Re: 04 Merc 50hp 4stroke BigFoot EFI - water in oil, locked up

it' s possible for it hydro lock, with water in cylinder. head gasket, overheat from bad impeller or tstat, cracked block, cracked head. all could be the cause.
 

smithtr11

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May 21, 2007
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Re: 04 Merc 50hp 4stroke BigFoot EFI - water in oil, locked up

So i talked with my dealer yesterday and he said it was just hydro locked. Seems to be a blown head gasket. The only reason for it to blow a head gasket is if it got hot, correct? When i mentioned this to the dealer he said not really, there are many reasons for a blown head-gasket other than over-heating. that's a new one to me. Thoughts?
 

j_martin

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Sep 22, 2006
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7,474
Re: 04 Merc 50hp 4stroke BigFoot EFI - water in oil, locked up

Overheat, uneven head surface, uneven or low head bolt torque, defect in the gasket itself, misfire, wrong moon phase, Murphey get's lucky.


hope it helps
John
 

smithtr11

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May 21, 2007
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Re: 04 Merc 50hp 4stroke BigFoot EFI - water in oil, locked up

that's what i figured.....I have read in other posts/forums about the temperture/overheat alarm, is a '04 50hp EFI supposed to have this warning?
 
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