1968 40hp Evinrude leaking like a sieve help!

Hi y'all first time post looking forward to some help. I've been retooling this outboard have it running perfect. The problem is when I shut it down out of the exhaust housing is dripping gas...I know that old outboards will leak some, but we're talking about some large drops and it continues for some time after I shut down. It comes out of the port just above the prop. I don't want to contribute any pollution to my beloved lake so I can't launch until this problem is fixed! I have done three adjustments to the carburetor float and what seemed to work best was when I only allowed the float needle to BARELY open. The problem with that adjustment was that the needle wasn't letting ANY gas to the engine. Everything has been by the book for low speed adjustment carburetor rebuild has been done too; both cylinders are firing...so why do you think there would be this "extra" gas? Am I running too rich or not rich enough or is something not closing? There is no extra gas at the carburetor only at the exhaust. Please help.

Re: 1968 40hp Evinrude leaking like a sieve help!

Hi redwing. Welcome to iboats and the world of 2-stroke (aka 2-"smoke") outboards. If your motor really is firing properly on both cylinders, then it's probably burning the fuel as well as it can. These old motors, can leave quite a bit of unburnt fuel, which then mixes with the exhaust gases and water to fol the goo you're referring too. The good news is that the problem looks worse than it is when you're running the motor in a test tank and will be greatly lessened once you're out on the open water. Be sure you're using the proper spark plugs (Champion J6C, or J8C if you do a lot of low speed trolling) along with a 24:1 fuelil mix which comes out to about 5.5 fl. oz. of TCW-3 marine 2-stroke outboard oil to 1 US gallon of 87 octane gas. Once you've got everything dialed in your motor should run just as clean ans any modern motor. I get a puff of blue smoke at start up on my '66 20 hp, but then it runs clean all day. I take it out in the water you see below. Here are some great links and vids to help familiarize yourself with your new toy. Holler if you get stuck.

http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1968&hp=40&model=40873D


Just some vids of what to expect:

http://www.duckworksmagazine.com/04/s/columns/max/24/index.cfm

http://www.youtube.com/watch?v=_mbR-4GcHHE

http://www.youtube.com/watch?v=cZmr9gasfH4&feature=related
http://www.youtube.com/watch?v=tYuaEtIUpmI

http://www.youtube.com/watch?v=vhy5EEF_gSU

Pics of where I take my "2-smoke", and I leave it just as clean as I find it.

Re: 1968 40hp Evinrude leaking like a sieve help!

As a 1968 model, it is safe to run at 50:1 ratio.

Re: 1968 40hp Evinrude leaking like a sieve help!

..... along with a 24:1 fuelil mix which comes out to about 5.5 fl. oz. of TCW-3 marine 2-stroke outboard oil to 1 US gallon of 87 octane gas.

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24:1 will really smoke....50:1 is the correct mix.

Re: 1968 40hp Evinrude leaking like a sieve help!

Thanks for your timely response! I only want to make sure on the fuel mixture...24:1? My manual says 50:1 and I had to double check on the spark plugs they are J4C's.Do you think this could be my problem? Thanks again...looks like I'll be launching today!

Re: 1968 40hp Evinrude leaking like a sieve help!

Personally, I run J6Cs in all my older Johnrudes over the original J4C recommendation. They seem to burn cleaner with less fouling. I have never had an issue with pre-ignition or detonation with them.

Re: 1968 40hp Evinrude leaking like a sieve help!

What gap do you have the J6C's? I know for the J4C's its .030" Thanks again for all of your help. I think I picked up a neat hobby along the way, this was a lot of fun to repair.

Re: 1968 40hp Evinrude leaking like a sieve help!

Same 030, and Im with Scott, I run the J6Cs in about all of my 50 OMCS regardless of hp.

Re: 1968 40hp Evinrude leaking like a sieve help!

i have seen biodegradable oils for obs at CT, havent tried it, but hear it smells like french fries!

Re: 1968 40hp Evinrude leaking like a sieve help!

+1 on the J6C plugs, full synthetic or biodegradable oil, 50:1 mix. Make sure you have good strong spark on both cylinders.
If you are really concerned about pollution, get rid of the 1968 motor and get a 4-stroke or Etec. The old two-stroke isn't designed to be "green".

Re: 1968 40hp Evinrude leaking like a sieve help!

Tim Frank said:

24:1 will really smoke....50:1 is the correct mix.

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Nah, not at all. Plus, oil is cheap insurance for a 50+ year old motor.

Re: 1968 40hp Evinrude leaking like a sieve help!

So I went down to my local outboard mechanic who stocks the parts for my motor, and he said that my fuel filter should be changed as a hole in the diaphragm will cause the fuel to leak down...i changed it and? No change maybe not as much leaking, but still doing the same thing...$110 dollar lesson? Maybe oh well still enjoy working on this thing, maybe I won't trust that guy so much in the future. Tomorrow I'll get the J6C's and get started on the interior of this boat, a 1958 Wizard 12.5 footer. Bench broke today...so unable to launch! Figured I should follow up...thanks for all of your input and advice!

Re: 1968 40hp Evinrude leaking like a sieve help!

If you have a parts catalog and/or service manual, you might want to find the "crankcase bleeder valve" and read up on its function. I am certainly not an expert but it sounds to me like what you are experiencing is the normal results of the unburned fuel/oil mixture being purged from the crankcase into the exhaust housing. Good luck with that great old motor!

Re: 1968 40hp Evinrude leaking like a sieve help!

kfa4303 said:

Nah, not at all. Plus, oil is cheap insurance for a 50+ year old motor.

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My comment was simply that the correct mix is 50:1....at least that is what the manufacturer prints in their manuals. It is there for a reason.
For every well-intentioned person who says "more oil must be better", someone else will suggest "that too much oil (when it is a factor of two) can in fact introduce a number of problems".
Personally, I just stick with the owners' manual.
You can use whatever you like....but giving advice in these forums that contradicts the OEM's recommended lubrication spec is questionable....IMO.....and not very enviro-responsible.