Oops. Forgot to add oil when refilling gas tank.

[kmead]

Full disclosure: I had about 2 gallons of 16:1 ratio fuel in my 6 gallon tank, and then added four more gallons of recreational gas, forgetting to add any more oil. My wife and I then took the boat out with my newly tuned up 1960 Evinrude Fisherman 5.5 hp for a 90 minute maiden voyage on our local river, averaging about 6 mph. The engine ran well almost the entire time, except for one instance where it stopped abruptly. I was guessing a clogged fuel line, since this is the first time we used the outboard and the tank is quite old. After disconnecting the fuel assembly line and pumping some gas through it, the engine fired back up and continued to run well.
So any opinions on possible damage to the engine, and would that have caused the engine to stop abruptly, even though it restarted and ran well afterwards? Also, the propeller still spins freely after this outing, so doesn’t that mean the engine is not seized up?
Thanks for all opinions and advice. Fingers crossed!

[Tubs]

If you were running 16 to 1 you would have had about 16 oz oil remaining from the 2 gallons in the tank. 16÷6=2.6 oz per gallon. That’s 50 to 1. Enough with the oil we have today.

A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.

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kmead

[kmead]

Thank you. I came up with the same ratio basically, but wasn’t sure if that was good enough. I’m glad to hear it!
Is 50:1 good enough for routine use, or is 16:1 safer?

[RICHARD A. WHITE]

I would recommend going back to original….. While it “MAY” be ok…is it worth possible risking failure? You get to decide that, after all it is your motor.

Richard

http://www.richardsoutboardtools.com
classicomctools@gmail.com

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kmead

[Tubs]

I have motors from the 20’s to the 1960’s. Except for the very small single cylinder motors like Cubs, Pals, Mates , ect., I run 3 oz. oil per gal. 42 to 1. These motors need more oil to make the seal at the main bearings to run properly. I have a 1960 and 61 Evinrude lightwin. I run 3 oz. per. gal. in them. However if you cant remember to put the oil in the gas every time, keep doing what you’ve been doing. It saved your ass this time.

A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.

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kmead

[Don]

You mentioned the engine stopped…The engine may have actually “seized” due to insufficient oil in the mix.  The 1960 5.5hps had plain rod bearings, so the extra lubrication provided by the 16:1 mix is critical.   I’m hoping the engine stopped due to a fuel flow issue.

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kmead

[kmead]

I’ll continue with the 16:1 ratio just to be safe. Occasionally I learn from my mistakes, so hopefully I won’t forget again. The engine runs fine now, at least under test conditions, so it’s not seized up. Hopefully it will do well out in the open water.
Thanks everyone for your valuable input.

[kmead]

I guess I dodged a bullet, because we took the boat out this morning and it ran beautifully. Engine still stops abruptly about every 10 minutes. If I disconnect the fuel assembly line, pump some gas through it, and then reconnect it, the engine starts back up and runs great. There must be a recommended way to clean inside a metal gas tank. Can anyone provide that information or a link to it? Thank you.

[Don]

Is the inside of the fuel tank rusted/fouled??

[kmead]

I don’t know, I’m just guessing it is because of the age of the tank and the fact that it hadn’t been used in a long time. I haven’t opened it up yet to investigate.

[Author]

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