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Author Topic:   Oil Leak at Prop Shaft
TsTime posted 01-12-2004 09:59 AM ET (US)   Profile for TsTime   Send Email to TsTime  
Sad sight yesterday after flushing the 1984 75 HP Johnson.
I noticed what appears to be lower unit oil dripping from the prop shaft, small amount has run down the skeg maybe
2-4 ounces. I consider this a problem, any ideas?
WSTEFFENS posted 01-12-2004 11:23 AM ET (US)     Profile for WSTEFFENS  Send Email to WSTEFFENS     

Sounds as if your output shaft seals have failed. Around here (central Ohio and KY ) the most common cause of failure is the ingestion of fishing line on the prop shaft. It gets sucked onto the shaft and then cuts the lips on the seals.

Pull your prop and look for fish line. If you find it go get a seal kit and follow the instructions. As a professional mechanic (ASE) I have replaced the lower seals on V4 & V6 OMC engines in a launching ramp parking lot in a bind.

If the engine has never been resealed, take it to the dealer and get the works. Water pump rebuild and new seals top and bottom, along with the vacuum leak test.

By the way are you sure its gear oil not lube oil for the power head? You might want to pull the lower gear case plug and check for water!



Bigshot posted 01-12-2004 02:05 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Hold up....what color was oil? When you flush them the exhaust which is black oily mess runs down skeg. If it is gold or oil colored, then seal gave up the ghost.
kingfish posted 01-12-2004 03:25 PM ET (US)     Profile for kingfish  Send Email to kingfish     
Also, be aware that 2 or 3 ounces of oil is a *huge* amount under your circumstances, and if it really did leak that much you *should* consider this a problem.

Conversely, an extremely small amount of oil (1/2 teaspoon or even less) can produce quite a stain.

And I would add oil of a creamy color to Bigshot's color schedule, if you have picked up water from a bad seal as per Walt's post, or from a bad fill or drain screw gasket.


Sal DiMercurio posted 01-12-2004 07:04 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
As Bigshot mention, it just might be tcw3 oil thats mixed at 50.1 & when you idle for any distance, the engine only needs maybe 100.1 & the excess dosen't get burned off & it comes out of the exhaust & drips down the skeg.
If it's black as coal, i'll bet it's tcw3 that didn't get burned.
Cicada posted 01-12-2004 09:54 PM ET (US)     Profile for Cicada  Send Email to Cicada     
I have a 1978 70hp. Johnson. I think it may share some of the same major components as the 75hp. I got a little bit of a start when I saw black oil dripping off the skeg. I imagined all kinds of things being blown up in the engine. Turned out it was oil coming down from incomplete combustion. That was last year, had it tuned and didn't notice it this year. I wonder if there's a possible connection between air, water temp and incomplete combustion.

Sure worth checking it out. Learned a little more about the motor.

As an aside for anybody, when did Continental Motors discontinue production of outboard motors for OMC?


TsTime posted 01-12-2004 11:14 PM ET (US)     Profile for TsTime  Send Email to TsTime     
Thanks for the info, upon further review the amount 2-3 ounces does appear to be a tablespoon. It is as black as coal and appears to be sludge. Prior to purchase had mechanic check out, he said lower unit oil had no odor and was clean. This was the first time out and ran for about 1.5 hrs then flushed, parked and noticed sludge. Anyway to confirm this is oil not burned off?


Sal DiMercurio posted 01-12-2004 11:54 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
Thats what i figured, it's unburned tcw3 oil, not lower unit grease.
It's very common if you have idled or trolled before you shut her off.
If you had a vro oil delivery system, it shouldn't be there because the vro would cut back on the oil being delivered while at idle.
If you mix 50.1, then your not going to burn that extra oil off & it drips down the exhaust.
Don't even worry about it, it's normal.
Tom W Clark posted 01-13-2004 01:26 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

That oil you see is perfectly normal. Don't worry about it. It is just unburned oil from the fuel mix, as Sal points out. You'll get that, VRO or not. No worries.

TsTime posted 01-13-2004 09:28 AM ET (US)     Profile for TsTime  Send Email to TsTime     
Thanks everyone! I will be performing service, fluid replacemnts soon and will advise if anything suspicous is noted. Please define VRO and tcw3.
kingfish posted 01-13-2004 10:50 AM ET (US)     Profile for kingfish  Send Email to kingfish     
VRO = Variable Ratio Oil injection system
Tom W Clark posted 01-13-2004 10:58 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

TC-W3 oil is the oil you add to the gasoline to create the fuel mixture the outboard runs on. "TC-W3" is the standard set by the NMMA and stands for Two Cycle, Water cooled, third generation.

VRO stands for Variable Ratio Oiling, and is a proprietary system of OMC/Bombardier. (The other brands have their own similar systems.) It is a simple system where oil is automaticaly mixed with the gasoline at a ratio that varies between 50:1 at full throttle and 150:1 at idle speeds.

WSTEFFENS posted 01-13-2004 11:05 AM ET (US)     Profile for WSTEFFENS  Send Email to WSTEFFENS     

VRO "variable ratio oiling", A crankcase pressure driven oil and gasoline mixing pump used by OMC to more accurately ration oil to gas raito vs load and speed. IE: low RPM on engine, low oil requirement, high speed more oil for engine. This system has fans and detractors. I am a fan. Its weakness is leakage of vacuum and crank case pressure pulses to the pump and the oil delivery lines (the plumbing). Leakage, equals loss of oil and a blown power head. Good maintenance and attention to detail eliminates the potental problems. I have had 4 engines with the system and it works perfect for me. The pump (at least on V series engines) is located on the front port side of the engine and looks some what similar to a Jarvic 7 heart. It is black oblong and full of hose connections.

TCW3: "Two Cycle Water, forumla #3". Usually para-synthetic, or sometimes full synthetic. A specially forumlated lube for 2 cycle (outboard & PC) use, with low ash and deposit characteristics. I believe, (don't know for sure), the oils are color coded. Blue for para synthetic, and Pink for full synthetic. The reason for TCW3 is that it vastly reduces the ammount of carbon build up on piston crowns and intake and exhaust ports which degrades performance.

Hope this helps!


WSTEFFENS posted 01-13-2004 11:16 AM ET (US)     Profile for WSTEFFENS  Send Email to WSTEFFENS     
Hope I didn't step on your toes!


stefan posted 01-13-2004 12:32 PM ET (US)     Profile for stefan  Send Email to stefan     
Whew, I feel better now, thanks Bigshot and Co.

recently had to fix a tight throttle cable-PB Blaster is incredible stuff!- and when I put the muffs on and worked throttle a bit to make sure all was ok, I noticed that black oil coming down out near prop when I took muffs off.
I didn't think it was a leak, and you have confirmed my thoughts!

Tom2697 posted 01-13-2004 01:33 PM ET (US)     Profile for Tom2697  Send Email to Tom2697     
Any time you run that motor on ear muffs you will probably see that oil. It normally would escape with the exhaust and be "washed" away by the water surrounding the motor but, on the get the idea.
goodad posted 01-13-2004 03:20 PM ET (US)     Profile for goodad  Send Email to goodad     
Have been following this thread as I have similar problems with oil leakage only further up the shaft...If I troll alot at low speed/rpm, can I assume that there is a greater chance of oil leakage due to unused oil in the firing process...I have an older 1986 90 hp Evinrude that I am trying to keep going till the inevitable of repowering..Has a 2001 rebuilt powerhead with no signs of leakage from the gasket area...Just wondering...

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