1973 Evinrude leaks oil while running

[reilley]

Hello,

i was wondering if anybody can tell me where the oil (black and smell like gas) that is leaking out of the exhaust (i think its the exhaust) could come from. I made a picture which is available at http://www.gate2north.ca/motor.jpg
It seems to leak quit a lot since the water had a lot of black oil spots on it. The old owner told me that he was using a 40:1 mix just to be safe. I know this engine has a 50:1 mix and corrected it at the next refill. Is it just excess not burned oil or could there be anything else wrong with it? How long would it take to clean out the old fuel oil ratio?

1973 Evinrude 40 HP
Model #40354D

Any help would be appreciated.
Thanks
Chris

 

[rickdb1boat]

Re: 1973 Evinrude leaks oil while running

Could be he mixture or the engine could be running rich. Does it run good? Might try a decarb and see if that gets some of the gook out of there. Just run the old mix out and use 50:1. Sounds like that's what you have done, so it should be gone...That hole it's coming out of is to drain off excess water so the lower unit doesn't freeze and crack over the winter...

http://forums.iboats.com/bbBoard.cgi?a=viewthread;fid=36;gtid=1035563 ] Decarb[/url]

 

[RPJS]

Re: 1973 Evinrude leaks oil while running

What you have there is a mix of unburnt fuel, you get a lot of that with a 2 stroke engine, and exhaust carbon.
If as you say this engine has been run on 40:1 there will be a lot of carbon build up in it, as RIck advised it's time to do a decarb. Also if you run the engine a low RPM's when on the water, trolling etc, it is always a good idea to run at WOT for 10min or so to clear any muck out before you come off the water.

 

[reilley]

Re: 1973 Evinrude leaks oil while running

Thanks guys for your help.
So far the engine has been ruinning quit well except for trolling it will smoke (white/blueish) quit a lot and eventually go out but if its anything like a car that could be explained by the the carbon built up. I will try to decarb the motor and see what happens.

Anyway, Thanks a lot for your help, I appreciate it.
Chris

 

[F_R]

Re: 1973 Evinrude leaks oil while running

Smoking is natural and normal. That's the oil that you put in the gas being burned as it goes through the engine. It does not recirculate over and over as in a car. Two-strokes only use the oil once and then it is either burned or blown out the exhaust or drained overboard. Actually all three of the above. That is what you are seeing running out the drain holes.

You can reduce the smoke to almost nothing if you use Castrol Full Synthetic TC-W3 Outboard Oil at 50:1. It's friendlier to the environment too.