mercury outboard lower unit leaking oil, please guys any info would be great. thanx

[scott304]

hi i have, i believe a 1986-1989 mercury outboard, was giving to me by my dad, i had a mechanic change stator,power packs, starter all wiring harnesses pretty much new. My prob jus occured when the weather got down to 18-25 degress, on the propellor there are like rubber oblong peices size of dime on the prop, 2 of them are missing and ive got oil leaking from my prop area and it milky looking like water got into it, and like a lite spray of oil water mixture coming out of 2 exhaust ports, my question is if i jus drain the gear lube and get news rubber peices that r missing would that fix my problem or do i have a bigger fix ahead of me??? The motor cranks,idles fine but acts like it gets bogged down after few minutes n dies.

 

[redjmp]

Re: mercury outboard lower unit leaking oil, please guys any info would be great. tha

Not sure what these rubber peices on the prop are? Can you post a pic? Have you removed the drain plug from the lower unit to see if the gear lube is milky? Are you premixing the oil with the gas? Anything that comes out of the exhaust ports has nothing to do with a leaky lower unit. If you see oily residue there, it is simply unburnt fuel. Sometimes this residue collect inside the exhaust tube and works its way down to the prop where it might get mistaken for a leak. Gear oil has a very distinct odour....

 

[Bob_VT]

Re: mercury outboard lower unit leaking oil, please guys any info would be great. tha

Welcome to iboats.

Well..... if it is a 2 stroke motor .....you will always have water and oil coming out of the exhaust. Unburned fuel oil mix and water will always be at the exhaust.

I am kind of confused about the rubber pieces ???? Can you post a picture of where they should be?

Changing the gear oil is always a good idea and a cheap insurance for proper maintenance

 

[scott304]

Re: mercury outboard lower unit leaking oil, please guys any info would be great. tha

okay guys ill get a pic posted asap it dark where i am but ill have it first thing in the morn. where the rubber looking things are i know there is something that is supposed to go in the holesill pic it and post for sure..

 

[scott304]

Re: mercury outboard lower unit leaking oil, please guys any info would be great. tha

here the rubber things, see there are 3 holes first pic the rubber plastic thing and the other to holes is missing what i think are suppose to be two more, and u can see right down into prop assembly, the thing that isnt missing keeps water outta there im guessing but what are these things called?????

 

[scott304]

Re: mercury outboard lower unit leaking oil, please guys any info would be great. tha

maybe one of you guys can enlightin me, im not sure what happining. Or maybe im mixing to much oil in the gas?? i do 50:1 jus like back of the quicksilver says. with high octane gas, should i run it little more lean see if my prob goes away?? oil in lower unit was deep gray with no large shavings.

 

[RadarRick]

Re: mercury outboard lower unit leaking oil, please guys any info would be great. tha

Your gear oil sounds good - not milky and no water.

Read again what REDJMP says: 2-cycle outboards always discharge some unburnt fuel/oil. You'll see more discharge if you're mostly trolling and it's especially noticeable when running in a barrel. I wouldn't worry about it - it's perfectly normal.

I also wouldn't mess around with a leaner mixture - you risk ruining your engine.

As far as the rubber bits on the prop - not sure what their function is - open them for access to remove prop? In that location, they would not be for sealing in the gear oil. Whatever their purpose, you should probably try to replace them.

 

[ONERCBOATER]

Re: mercury outboard lower unit leaking oil, please guys any info would be great. tha

if i am looking at the prop correctly and your talking about the vents cut into the props hub, the intention is to allow exhaust gasses to be drawn into the propeller at low speeds to free the prop to turn up faster into the power band, and then at high speeds be plugged by water giving you full prop grip on the water so you can go faster.... sometimes done on boats with a planing hull and marginal HP to allow the engine to make peak hp to get out of the hole. Most times when done OEM they are round holes and come with inserts that can make the hole smaller or completely fill it. If you plug the holes up then your prop will hook up better but your hole shot may suffer. Those particular holes look like they were done to the prop AFTER it left the manufacturer.

attached is are a few links about the subject, it was also covered in the johnyrude manuals
http://forums.iboats.com/showthread.php?t=12784&highlight=prop+drill+hole
http://forums.iboats.com/showthread.php?t=413518&highlight=prop+drill+hole

hope these links answer your ?s
sean