johnson 9.9 milky fuel in combustion chamber

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clairmarinelighting

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Apr 3, 2016
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HELP!!! I have a 1985 Johnson 9.9hp outboard with a compression ration of 122psi equal on both cylinder. when I bought the engine 8 months ago it was 130 psi in both cylinders. fuel mixture is dead on 5o to 1 ratio. .non vented tank. the fuel is new as well as the tank. last time I went out I didn't start on the fist pull like it normally did, when I got home I checked the cylinders by pulling the plugs and found a milky substance( oil and water) so I replaced both lower crank seals and associated gaskets orings etc...I replace all water jacket gaskets. and intake side panel gaskets...but still milky. any ideas? the head appeared to be fine no indication of damage or cracks. I have a descent background in 4stroke but I suck in 2 strokes....I have buit several small black race motors and trans..
 
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clairmarinelighting

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still starts on first pull...motor has been rebuilt before I got it. its running in a 50 gallon barrel now...id rather it break at home than on the water....sooooo weird
 
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clairmarinelighting

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gasket surfaces were in good shape.. no pitting used mr gasket non hardening to stick gasket...but VERY little as to not get it in passages...but not on head gasket.............or orings......
 
GA_Boater

GA_Boater

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Welcome aboard.

Are you padding posts or what? All you're doing is repeating yourself. Give a little time for members to see your thread. The thread is only 2 hours old. :facepalm:
 
oldboat1

oldboat1

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Might pull the head again, and resurface it before replacing (should be able to reuse the gasket). If the t.stat cover isn't leaking, would leave it -- assume the new t.stat is working OK, and installed correctly (head surface temp somewhere around 120-140). Over 160 is too hot, but don't want it running cold either.
 
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Crosbyman

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seeing this is so odd,,, i would try to pressurize the "water circulation system" with air via the water tube in the lower gearcase

air should only exit were water would exit...out the engine . anywhere else would point to a water leak internally

just an idea...
 
pro-crastinator

pro-crastinator

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Dec 12, 2013
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IF i had access to one of those probes that lets you LOOK inside the motor, I would poke it in the lower end to look at the crankshaft where the connecting rod is attached and see whats there.

The hose - or tube that pumps oil from the bottom to the upper areas of the motor - is it intact?
 
pro-crastinator

pro-crastinator

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Yes, or if theres a minor leak in the exh housing, I would only be concerned if the "milk" was undermining the bearing surfaces.
Also, I wonder if there was a picture of the milky mix available.
 
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clairmarinelighting

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Apr 3, 2016
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Decided to take it out anyway..i've been on two fishing trips now and one trip to the sandbar...yet still running...compression is still the same..My question is if the thermostat is removed (which it is) is this the outcome?..also there could be an exhaust leak in the gasket where the exhaust tube meets the lower unit. I need to replace that gasket....im going out again today, I will take pics and upload them...thanks guys...
 
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