1995 3.0 liter 225 mercury carb. leak

[Sea Hawk]

after running all day, I raise my motor for the night. The next day I notice there is oil running down the control cables. not a large amount, but enough to be noticed on a white deck. I removed the cowling and saw a bit of two stroke oil laying in the bottom under the carbs. It appears that it is clean unburned oil that is running out of the carbs when it is tilted up. What could cause this and is it a major problem. I have looked all over the motor and have found no other leaks or wet, oil soaked areas. Any ideas?

 

[Reel Appeal]

Re: 1995 3.0 liter 225 mercury carb. leak

Hi Sea Hawk,<br /> I have a '96 Johnson 225 that does the same thing.I think alot of outboard owners encounter this situation.The gas/oil mixture in the carbs is spilling out(albeit a small amount) into the airbox(on front of carbs)whenever the motor is tilted up.The gas in the airbox eventually evaporates leaving oil to leak through the motor cowling onto your nice clean boat.Also had a '86 Merc.175 w/same.Usually this is not a problem unless it is excessive(which might indicate a carb/float problem).The only way to avoid this is to shut off fuel supply to motor and run engine till out of gas/stalls,then Tilt.You might want to remove the cowling and check the drain/screws on the carbs to make sure they are tight.Also,are the carb bowl gaskets good?One(or more)of the carb floats could be stuck open(allowing carb to dump fuel)although this is unlikely if your motor runs OK.If you are using more fuel than normal check under the hood for leaks.If not,does not sound like a real problem.

 

[Greg Lawrence]

Re: 1995 3.0 liter 225 mercury carb. leak

on my 60 hp johnson it does the same thing.. it seems to come from the nipple on the front of the intake manifold, so i reassembled the airbox, seald it to the carbs with permatex, and hooked the drain from the airbox to that nipple on the manifold. i havent seen one drop o gas-oil.

 

[Sea Hawk]

Re: 1995 3.0 liter 225 mercury carb. leak

Thanks Reel and Greg. I certainly appriciate your help. I will do a little more investigating and make sure that there are no other possible problems. Then I will chalk this one up to being the nature of the beast. I was concerned at first, but now I feel much better. Hope I can return the favor some day. Thanks again and happy boating.