Oil and Gas Leak on 90hp Mariner

[Crappiefishing]

I have a 94 90hp Mariner, I notice that in the back of the boat under the motor there is oil and gas mixture leaking from the engine, can anybody help with this? I thought it was just oil leaking from the top of the oil tank but I notice it's a mixture of oil and gas. Thanks

 

[Laddies]

Re: Oil and Gas Leak on 90hp Mariner

If the engine is tilted up without runnig the fuel out of the carb they will drip I don't know if this is the problem or the inlets are sticking

 

[sport15]

Re: Oil and Gas Leak on 90hp Mariner

I have an '87 70hp Merc that does the same thing.. I reviewed the FAQ, only found "its a poor design and you have to run the gas out", searched online and then was told by a local dealer "Mercs always do that.." Not the best answer. So, I took a piece of IV tubing and stuck it onto the overflows and led the ends up higher then the top of the bowl on the respective carbs. This stopped the leaking over flows with the engine tilted but now it makes the oozing main jets more obvious. All the floats are set and inlets are clean.<br /><br />If the IV trick helps great, if not, as Red Green said, "we're all in this together".. Anyone else got an idea?<br /><br />Dave

 

[mtnriverdog]

Re: Oil and Gas Leak on 90hp Mariner

I recently received a lot of help from the forum on my '95 125 merc. This what I did to stop the exact same problem. Replaced the bottom gasket on the air intake cover, bought a transom saver to keep the motor lower instead tilting all the way up and when I take out I tilt the motor all the way up with the motor off and then right back down. This seems to let any unspent fuel run out of the carbs and then down to the drip pan. Everybody told me that any merc they ever saw or owned did this.<br /><br />MDOG

 

[mtnriverdog]

Re: Oil and Gas Leak on 90hp Mariner

One more thing. Several people have told me to disconnect the fuel line while the motor is running and let it run out of gas. I have not tried it. Any comments?<br /><br />MDOG

 

[sport15]

Re: Oil and Gas Leak on 90hp Mariner

Mdog<br /><br />Running the gas out worked too... Then you read in other sections of the forum and the boys say to be careful of that 'cause if one jug goes dry first then it is getting no oil.<br />Not that helpful but there you go.<br /><br />JB, what say you?<br /><br />Dave