oil leaking from lower unit

[refractory148]

I have 1998 25HP Johnson Model# J25RECB. I just purchased this motor on a small alum. boat. I brought it home and hooked it up to the water hose with one of those motor rinsing adaptors. I ran it for about two minutes. Everthing was fine it ran great and water was coming out of the pee hole. When I shut the motor off oil started to come out of a small hole at the top of the lower unit closest to the boat. The hole is maybe 1/8" and is located between the two "fins" on the lower unit on the port side. Is this a major problem or does the lower unit just need new seals? I drained the oil and it looked fine. Did not appear to be any water or any metal shavings in it. What made this happen???

 

[OBJ]

Re: oil leaking from lower unit

Welcome to the iboats forums refactory148..<br /><br />That hole is a cavity drain hole. Lets out any water that could freeze in cold weather. If the "oil" you saw was a dark black, it's most likely unburnt oil from the exhaust. Happens. Check the fuel/oil mix. Should be 50:1 mix. That's 16oz of oil for 6 gal. of gas. You may want to also check the spark plugs/replace them. Poor spark can cause poor combustion and give the same results. <br /><br />But if ya' checked the lower gear lube and it had no water in it, ya' should be OK to go.<br /><br />Hope we've helped.

 

[refractory148]

Re: oil leaking from lower unit

The oil I saw was a dark black but it was an awful lot of oil. I would estimate that there was 2 oz. of oil that came from that hole. I will check the fuel mixture. Im still using what was in the tank when I got the boat. This still worries me very much as I have never seen an outboard do this before. I will add that when I ran the motor for those couple of minutes that it was smoking pretty good.

 

[refractory148]

Re: oil leaking from lower unit

Also want to add that I have not yet ran this motor in water. I just got it. Also the person I bought it from told me they had just had it tuned up, spark plugs, adjust carb. and change lower unit lube; so there not being water in lower unit doesnt make me feel any better. Is it possible that lower unit oil could get into this cavity??

 

[Cricket Too]

Re: oil leaking from lower unit

Well you said it was dark black so that rules out lower unit oil if it was just replaced because it is not black. Most likely it is unburned 2 stroke oil. This happens to me even with a 50:1 mixture and it is normal, especially if you idle alot before you shut the motor off as you were in your driveway on the earmuffs. Everytime I come home and flush out my Johnson 70hp on the muffs I come out next day and there is a little puddle of unburned oil. The unburned oil builds up in the exhaust and then when the motor is shut off gravity causes it to drip down and out. Good luck with the new boat and motor.

 

[refractory148]

Re: oil leaking from lower unit

Ok guys thanks for all the help. I have asked around a couple people I know and everyone has the same answer so I feel better now about running it ill just keep a close eye on things. Thanks so much for the help. Im glad I found this site.

 

[waterinthefuel]

Re: oil leaking from lower unit

My 28 does the same thing, the black oil actually puddles up on the cavitation plate. It's just residual oil from the gas, nothing to sweat.