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HELP! Oil coming from lower unit


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Ok so heres the deal I first notice the oil coming from the weep hole on the lower unit about two summers ago so I removed the lower unit to 1. Replace the water pump and 2. Find out where the oil is coming from. After getting it off the oil seems to be coming from the exhaust so I cleaners it all out of the chamber flushed the lower unit replaced all seals and gaskets, put it all back together and still doing it. It only happens after running the boat and leaks for about a day then is done. Its a older (74) evinrude 85 HP I mix the gas and oil very cautiously and use Pennzoil. The spark is strong and the motor runs great I have done compression tests on the 4 cyl they seem fine but have not done a leak down test. Its not gear oil and I have had the the lower unit pressure tested all good there. Any Ideas or advise would be greatly appreciated were having a new driveway put in and the wife wants it fixed so it doesn't ruin the driveway or she will make me sell it HAHA. Thanks in advance

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Its not lower unit oil I know that for sure it doesn't smell like gear oil but it does have a burnt exhaust /fuel type smell. The only issue I have with it is that there is so much of it when it does leak out. Ive been going through the manual and found a few small issues with the timing. It was about 3 degrees advanced so I set it back to factory spec hopeful I can get out later and take it for a test spin and see if it made it better or worse. Last year I rebuild the carbs and reset the timing it was way out but ran well I wrote everything down before I did it so I could set it back to what it was but it was about 7 degrees retarded before I started. Setting the timing is a big pain in the rear cause the boat doesn't have a tach that I trust. Guess ill keep tinkering for now.

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I'm pretty sure it sounds like unburned oil and gas mixture my older two stroke 9.9 Johnson does it sometimes but mine is usually a darker color than above

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I have a old Evinrude 15 hp kicker, does the same thing I pulled the lower unit down replaced the water pump the O rings and the O ring that goes around the copper pipe into the motor, and when I replaced the O ring on the copper pipe it must have slid off and I had the same thing going on as you have, so I called Henry down at Beltzville Manner Marine and he asked if I replaced the heavy O ring in the copper pipe and I replied yes. He said to come down and he would give me a heavier in the thickness one so I pulled it a part again and I couldn't find the other "new" one so I put the heavier one on and no more oil leaks out the weep holes anymore, a little out the exhaust and its not the seal I replaced that one also, my motor is a 78 and that little oil is unburned oil/ gas mixture. It's only a little puddle about the size of a $.50 piece.

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  • 2 weeks later...

My 7.5hp johnson does it when I first start it when I start my troll.  You look behind the motor in the water and see this filmy brownish cream shoot out of the prop exhaust.  Unsightly but completely normal, usually it is just the unburnt fuel and oil mixed with the water in the exhaust.

Edited by Chas0218
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Ok guys thank you for all the suggestions and ideas it is unburned marine sta-bil that I add to the fuel ....I put some of the fuel from my tank in a suitable burning container (beer can cut in half) and put a match to it when it was burnin the only thing left was a gooey tar substance. So I tried it with just gas and oil no goo. Highly scientific if I do say so myself. Guess its no more sta-bil

Sent from my SCH-I535 using Lake Ontario United mobile app

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Hmmm interesting, I too run stabil. Here is my observation my big motor (oil injected) does not do this. My kicker motor is not oil injected and does this. I wonder if it has something to do with the mixed gas. I do rev up my kicker when I'm done trolling and it blows it all out.

Sent from my thinking car!

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