Topic: 1957 Johnson 35Hp Seahorse oil discharge in water

This topic has 9 replies, 9 voices, and was last updated 5 years, 11 months ago by amuller.

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May 27, 2018 at 11:12 am #10056
dcygan
Participant
This is my first time posting on this forum. I’m looking for advice on whether or not it is normal for a 1957 Johnson 35Hp outboard to be discharging oil into the water. I did a partial rebuild, gearbox, impeller, and ignition system to get it up an running. I have not done anything to the powerhead. It seems to sound good when running at idle with it immersed in a 32 gallon trash can full of water. My problem is that it creates a lot of blue smoke from the 2-cycle oil being burned and a lot of unburned black oil also being discharged into the water. After about 5 minutes, a 3-4" diameter pool of black oil forms near the front of the lower housing (the oil pools together from the turbulence of the water as the engine runs, but quickly dissipates once the engine stops). My question is, is this normal or not?
Thanks,
Doug
May 27, 2018 at 11:20 am #76799
crosbyman
Participant
Canada Member - 2 Years
normal ..black is oily carbon oils are not black

Joining AOMCI has priviledges 🙂
May 27, 2018 at 11:46 am #76801
jerry-ahrens
Participant
US Member
All of what you have described is normal. Actually, any modern 2 stroke outboard motor will do the same thing when ran in a barrel, trash can, test tank, etc. That black stuff is unburned fuel/oil mix that exits the motor through the exaust. As for the smoking, that is the 24/1 fuel mix. DONT try to use less oil… these old motors smoke, nothing to worry about.
May 27, 2018 at 12:15 pm #76807
frankr
Participant
US Member
The same question gets asked almost every day on various forums. Yes, it is normal Don’t fret about it. It also is why motors built nowadays are 4-stroke.
May 27, 2018 at 12:22 pm #76808
kerry
Participant
US Member
Synthetic 2 stroke oil will reduce the smoke.

If you have too many, AND not enough, you're a collector.
May 27, 2018 at 12:35 pm #76812
outbdnut2
Participant
US Member
As the others said – it’s normal, especailly on startup and during warmup. To reduce the mess in your test tank, squirt some liquid dish soap into the water. It will break down the oil, just as it breaks down grease on dirty pots and pans. You will immediately see it work if you already have oil on the water. Not too much dish soap or you can end up with soap suds bubbling out of the tank as the motor churns it up.
Dave
May 27, 2018 at 2:28 pm #76818
dcygan
Participant
Thank you all for responding and reassuring me that this is normal. I just bought a gallon of Pennzoil Marine Synthetic Outboard 2-Cycle Oil, which says in their spec sheet is biodegradable. I’ll give that a try and see how it goes. Has anyone tried this before?
May 27, 2018 at 2:45 pm #76820
The Boat House
Participant
That is what I have used for years but it has been discontinued.
There are other brands of biodegradable oil if that is important
to you but they are quite a bit more expensive than the Pennzoil.
If they have any more of the Pennzoil left I’d go back and get it.

https://www.ebay.com/itm/Bel-Ray-Marine … SwldRZ6lm1
May 27, 2018 at 2:56 pm #76822
Steve D
Participant
quote Kerry:

Synthetic 2 stroke oil will reduce the smoke.

I have found the same thing, less smoke, less oily sheen, just keep using the recommended ratio for your motor (others have their own thoughts on that).
May 28, 2018 at 10:59 pm #76936
amuller
Participant
Motors up until sometime in the 60s usually had crankcase drains that went directly into the water. Later on, under some pressure from EPA, they were set up to recycle that drainage. If you poke around on this board you can find discussions of how to divert the drain mixture into a catch bottle or back into the tank. IMO, this is worth doing if you plan to use the motor extensively. It won’t eliminate all the smoke and oil sheen, but will reduce it noticeably. Combine this with modern high-quality oils and you have a cleaner motor.
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