83 johnson gt150 lower unit oil leak

[motodave]

Hi all,
I have been reading on here for a few weeks now, there is a lot of helpful people on here and I have enjoyed the info, I am not new to boats but am a first time owner, so here goes my problem:
Bought an 83 ranger 372v with a 83 Johnson gt150 on the back a few weeks ago. Took the boat out for the first time and although it ran good on plane, it did not want to idle while in gear. Carbs were flooding so I ordered oem kits and replaced/cleaned the carbs, replaced worn fuel lines, etc. Put the motor on muffs and fired it up, idling pretty well now and no bad leaks, just those weep holes which Im reading is fairly normal. Anyhoo I was getting ready to put the boat in the water and I noticed a small oil leak on the lower unit, left side of motor right where the bottom housing seals up which I did not see before. Its not an excessive amount but it is very black (was planning on changing gear oil). Smack dab mid way across the seal. There is no oil coming from propeller area. Im trying to figure out how to post pics. My question is, how worried should I be at this point and should I tear it down before I test the boat again? Not seeing a gasket on the schematics is rtv type sealant used instead? Thank you for your time and any and all help!

Dave

 

[motodave]

pic

 

[Will Bark]

That appears to be unburned oil/gas coming down the inside of the leg and is not harmful; there is no gasket or sealant used at that section. Gurus will probably chime in with thoughts on this but at this point I'd leave it alone and put the boat in the water. Good luck.

 

[motodave]

Will, many thanks for your response! I just read a sticky that mentioned that it could be unburned gas/oil, theres a ton of helpful info and people on this board thanks again. I cant seem to wrap my head around the fact that its vital to keep water out of the lower unit, and theres no gasket or sealant used, crazy to me. I think I will change gearcase oil and double check for water, just to be safe.

 

[racerone]

That area where you see the leak is not sealed at all.----In fact it is flooded with water when motor is not running.----The lower unit seals keep water out and the oil in.----The lower unit is sealed and totally seperate from where the exhaust and cooling water exit the motor.

 

[emdsapmgr]

Black, oil, tarry residue is probably unburned fuel coming down the exhaust tube. Not usually considered a problem with the lower unit itself. Normally this black liquid all exits the prop area. It's untypical for it to exit at the top of the lower unit. If the lower unit was recently off for a change of the impeller, it is possible that the lower exhaust seal is either missing or became distorted during reassembly. In any event, it may be permitting the exhaust to bleed around the seal and out at the top of the gearcase, as seen in the picture. While it's not a fatal problem, you should consider replacing it sooner rather than later. That exhaust will continue to bleed around that seal (320961) and can bleed onto the top of the composite impeller housing. That excess heat could reduce the life of that housing over time.

 

[boobie]

To make yourself feel better take the motor into a dealer and have the lower unit pressure and vacuum checked for any leaks.

 

[motodave]

Thanks to all you guys for the replies, really helps me out and now I will sleep much better! Glad I found this site!

Dave