1970 18hp Evinrude Fastwin Lower Unit Leak?

[glock22ownr]

Hey guys, I bought this motor and boat during the winter. I don't know much about it's history other than it actually looks like it's in top notch shape, and runs very well. The problem is that after I ran it I noticed a strange leak coming out from the lower unit. The liquid smelled exaust-ish and was rather thin. I just replaced the gear oil before I ran it. The stuff that came out was a yellow-ish sand color oil, so I assume it had water mixed in. I put in 85 -120W gear oil and it was rather thick, whatever this was didn't look like that. It appeared to be more of a thinned down version of the crap that was in there before. Just wondering if anyone has any ideas. Shot some video of it and put it on youtube, here's the link:

http://www.youtube.com/watch?v=UExxNyZ7mDI

I'm hoping the lower unit isn't cracked or something and I just need some gaskets or whatnot.

 

[Joe Reeves]

Re: 1970 18hp Evinrude Fastwin Lower Unit Leak?

Probably just excess unburnt mixture draining down thru the long exhaust housing, however keep your eye on the gearlube just in case.

 

[glock22ownr]

Re: 1970 18hp Evinrude Fastwin Lower Unit Leak?

Ok, it sat in the garage overnight and more junk came out. It's the color of used motor oil now ( so dark ) and still smells like gas / exhaust. It's a thinner than motor oil though. Here's more video :

http://www.youtube.com/watch?v=unNNjsDETBY

I looked at the plugs and the lower one needs to be replaced for sure, so I'm going to get new plugs and see what happens. Let me know if you guys think of anything else based on the latest. Thanks again !!

 

[glock22ownr]

Re: 1970 18hp Evinrude Fastwin Lower Unit Leak?

So, I hate when someone posts a problem, it gets fixed and they don't post again... So here goes.

I replaced the plugs and cleaned out gunk by the lower unit. Then ran the engine for about 20 minutes and no more gunk leaking! There seems to be a lot of smoke coming out now, which my friend and I suspect is a timing issue. We'll see, but if that's all that's wrong I'll take it. I'll post again about the smokey issue so the thread's complete.

PS: Thanks for the reply Joe

 

[Joe Reeves]

Re: 1970 18hp Evinrude Fastwin Lower Unit Leak?

You don't say what mixture you're using in that engine. You can safely use the 50/1 mixture which will keep the smoke problem at a minimum.

 

[glock22ownr]

Re: 1970 18hp Evinrude Fastwin Lower Unit Leak?

Yep, 50:1 is what I am running. I'll get some video of it running in the next day or two and post that.

 

[reddaddy]

Re: 1970 18hp Evinrude Fastwin Lower Unit Leak?

i have the same problem. rebuilt water pump and seafoamed engine out. oil is coming from exhaust housing and pours out the same hole as yours.what i want to know is how. i was under the impression the crankcase also required primary compression.if thats true (and i believe it is),then is it possible that the oil is there because the lower crankcase seal is leaking???? just speculating, i really don't know but can anybody else tell me.

 

[MattinTally]

Re: 1970 18hp Evinrude Fastwin Lower Unit Leak?

I've got almost exactly the same issue with my 1971 18hp. Its leaking a substance similar to the first YouTube video posted, but NOT like the 2nd video. My leak is coming from two weep holes that are just below the bolts that bolts the lower unit to the exhaust housing. Is there any explanation for this? I pulled the drain plug and the oil in the lower unit looked fine. I too have been working on my motor with new coils, points, condensors, plug wires & boots, carb kit & new fuel pump. Any ideas what this leaking substance is and if its cause for worry?

 

[MattinTally]

Re: 1970 18hp Evinrude Fastwin Lower Unit Leak?

Here's a photo of the leakage that I'm seeing from two small weep holes.

Is this just exhaust leaking out?.... or is this something that I need to worry about?

 

[samo_ott]

Re: 1970 18hp Evinrude Fastwin Lower Unit Leak?

Those are the machined drain holes. It's supposed to drain the water out of the LU housing. You do seem to have a lot of oil in it though.

 

[F_R]

Re: 1970 18hp Evinrude Fastwin Lower Unit Leak?

Been running it in a barrel?

 

[MattinTally]

Re: 1970 18hp Evinrude Fastwin Lower Unit Leak?

Yes, its been running in a trash can. Motor was purchased in Nov. of last year from an elderly gentleman who had to get an electric-start as he could no longer start a pull-cord motor. According to him, motor sat in barn for about 6 years unused. I replaced all ignition compontents, carb, fuel pump, plugs & plug wires, and fuel lines. Just got it running after a few weeks of tinkering with it in my spare time.

Why does running it in a barrel produce excessively dark and thick exhaust?

 

[screennamie]

Re: 1970 18hp Evinrude Fastwin Lower Unit Leak?

Yes I have the same thing going on... why would running it in a barrel cause this black oil?

 

[kfa4303]

Re: 1970 18hp Evinrude Fastwin Lower Unit Leak?

HI Mattin and screennamie. The black residue in the test tank is unburnt fuel oil mix that is mixed with the exhaust gases and expelled out of the back of the motor. Gotta remember these old girls were built in the days of super cheap gas and before modern environmental restrictions. While the problem is particularly noticeable while running in a test tank, it will practically disappear when you get on the open water. Your motor should smoke much less too. When it's in the tank it recycles the same oily/exhaust gas filled water over and over which only compounds the oily water problem, but don't sweat it. You'll be fine on the big water.