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15hp 4 stroke - Oily fuel smelling stuff dripping from air intake box - from hose at top of block? Any Ideas

N

NH1

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15hp 4 stroke -
Oily fuel smelling stuff dripping from air intake - from hose at top of block? The air intake box has a little hose running from the rear top up towards the rear of the engine and enters top of the block under flywheel cover...

When the engines fires with the hose removed from the airbox there's a blow back from that hose with dark looking oil that smells like fuel intermittently shooting out. Normally this will blow this fluid into the air intake box - through the carbs and into the cylinder/s.

The 2 attached pictures will give you the ideas of where the air box hose is, next picture where it comes from numbered 29.


Any ideas why that has happened? What the fix would be - or do i go get another engine?

Thank you for any help.



15 mercury 3.JPG
 

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racerone said:
Crankcase ventilation.----Check oil level.
Click to expand...
Hi Thank you for that. The oil level seems oddly high. Will check that tomorrow in daylight. Also the oil, stank of fuel. So yes crank case vent. The blow back from the rings in to the crank case - the oil has thinned out with un burnt fuel - explains why it stinks and is not a real engine oil consistency. Will drain it down - give it some fresh and see if it helps.
 
Fuel pump seems ok. Engine will start first pull when cold. But tends to die out when warm at low revs. Then will refuse to start till cold.. Oil changed out for new - new fuel pump on way but i fear the rings are damaged? So compression test is next also the engine is smoking more when running... Mm mm any idea on these symptoms.
 
News :p:p:p- Today i stripped the carb - cleaned every part as i have normally done in the past, reset it all and boom... Engine is now running like clock work again.. Starts first time every time on half pull :) hot or cold :) Still not sure why the fuel dumped to the crank but the new oil is free of fuel.
 
NH1 said:
Fuel pump seems ok. Engine will start first pull when cold. But tends to die out when warm at low revs. Then will refuse to start till cold.. Oil changed out for new - new fuel pump on way but i fear the rings are damaged? So compression test is next also the engine is smoking more when running... Mm mm any idea on these symptoms.
Click to expand...
 
Not sure, but I would check my timing. Ifvit gets off too far, your fuel pump will be trying to pump fuel into the cylinder while your intakes are open. Therefore, your pumping fuel straight through into into your motor pan.
 
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