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Old 07-01-2011, 07:51   #1
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Can I Put 50:1 Mixed Gas in a Four-Cycle ?


I was informed by another post a while back that it would be fine to run 50:1 mixed gas/oil in a 4-cycle outboard. The reason I want to do this is that I have a large fuel tank on my sailboat for the 15hp 2-cycle outboard, and I want to pump the pre-mixed fuel out of the same tank to refill the dinghy motor.

A friend of mine offered me an unused 2.5hp Mercury outboard at a great price. This is perfect for my needs, but it would be extremely inconvenient to keep a separate supply of pure gas just for the smaller outboard. Can anyone verify the opinion that running 50:1 in a 4-cycle will not cause me any issues?

Thanks a lot,

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Old 07-01-2011, 07:53   #2
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Although 50:1 is not all that much, you risk fouling the plugs.

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Old 07-01-2011, 08:06   #3
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Right. You can put it in and the engine will run. It will probably smoke a lot, you will gunk up your intake and foul the plugs, but it will run.

I sure wouldn't recommend it.

On the other hand, if you're getting the engine for free, and you don't mind a little extra maintenance, then maybe it would be worth it. In any case, it is definitely not true that it will not cause ANY issues. Whether or not the issues it causes are worth it to you, only you can decide.
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