Engineering Fuel In Outboards?

Anyone use the pre mixed 40:1/50:1 (2 strokers) or 4 cycle (4strokers) small engine fuel you find by the lawn mowers and weed eaters in an outboard? If so what were your results compared to regular pump gas with and/or without ethanol?

I asked my lawnmower shop the same question.
he said - - - - one is $25.00 a gallon - the other is $2.65 a gallon.
if you buy non-ethanol fuel (95oct) and add a little fuel stabilizer
with the appropriate 2-cycle oil mix and you can make your own [lawn equipment mix].
other than that - I have never even considered it [for an outboard].

Yeah the $20-25/gallon is a bit crazy. A $5 quart bottle will last me more than a month of weed eating unless I get tired of looking at my neighbors side of the ditch he doesn't seem to care to weed eat; then it's a month at best. Mainly was thinking about the smaller motors with internal tanks.

By the way Johnny want to say I enjoyed your article on the pressure treated wood a while back.

Pappy said:

You do NOT want to run air cooled 2-stroke oil in a water cooled outboard.

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Completely ignorant when it comes to things mechanical. Can you educate me on why?

RedHatRedNeck said:

Anyone use the pre mixed 40:1/50:1 (2 strokers) or 4 cycle (4strokers) small engine fuel you find by the lawn mowers and weed eaters in an outboard? If so what were your results compared to regular pump gas with and/or without ethanol?

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A nice strong quart can of fuel that won't go bad that is stashed in your boat may get you home one day.

RedHatRedNeck said:

Pappy said:

You do NOT want to run air cooled 2-stroke oil in a water cooled outboard.

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Completely ignorant when it comes to things mechanical. Can you educate me on why?

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Designed for very different operating temperatures. Air cooled engines naturally run hotter - therefore the oil you mix for an air cooled engine will be thicker than it needs to be when used in a marine engine that has water cooling it at all times because it will be at a much lower temperature in the marine engine. As a result you'll get oil building up and burning which will give you carbon buildup in your cylinders and wear them out faster.

Don't disagree with carbon buildup, but that would normally be in exhaust ports. I don't think carbon wears out the cylinder.

All the new oils are backwards comparable for air and water cooled engines. There is no difference anymore.

Thanks

Stumpalump said:

All the new oils are backwards comparable for air and water cooled engines. There is no difference anymore.

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Really??
Guess I'm Google bound...always was a difference....needed to be rated tc3 for water cooled

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Pappy said:

"onthewater" came pretty darned close.
The flash points between a TCW3 and a 2-stroke air cooled oil are different. Think the viscosity is about the same between the two. He nailed it on the operating temps between the two styles of engines.
This will indeed create excessive carbon in the exhaust ports, piston tops, and in the cylinder head.

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Thanks

All BS. New oils burn complete. This ain't the 70's. Want proof? Get the MSDS sheet and call that number. It's a direct line to the oil companies laboratories. I called it. Today's oils are so good they can be used in air or water cooled engines. I have not seen a coked up two stroke in a decade. All I see is squeaky clean.

I still dont know...
Why do some newer outboards(2 stroke) call for certain oils...warranty void if not used?
While I agree that newer oils have additives that help oils burn clean, some will probably have to reach certain temperatures before that happens.
I'm sticking with buying the proper symboled oils...one less headache

Pappy said:

"onthewater" came pretty darned close.
The flash points between a TCW3 and a 2-stroke air cooled oil are different. Think the viscosity is about the same between the two. He nailed it on the operating temps between the two styles of engines.
This will indeed create excessive carbon in the exhaust ports, piston tops, and in the cylinder head.

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Additionally, water cooled 2-strokes generally have tighter tolerances than air-cooled. This is because the water cooled 2-strokes have a narrower band of operating temperature (mentioned above) and shouldn't need the extra 0.001-0.002" slop to keep the piston from making the big squeak when it gets a little hot, like in an air-cooled application.

Typically the piston is aluminum, and the cylinder bore is iron. When the temperature goes up a given amount, aluminum expands more than iron does. *Squeak*

Big open-class air-cooled dirtbikes of the late 70s and early 80s were notorious for seized pistons. Heat expansion on a big 500cc piston is considerable. So we'd cut the bore a smidge oversize and allow for a thorough warm-up to mitigate piston slap and cracked piston skirts.

Home Depot 2-cycle oil is fine for a McCullough weed whacker. But I'd never skimp on cheap oil for an expensive 2-stroke.

Then there are crank seals, the other bane of 2-stroke motors. A bad wet-side seal can leak crankcase oil and make excessive smoke and foul plugs and/or the ignition side seal can leak air and cause the engine to run lean, hot, and cook itself. Many a "brand new top end" was destroyed because the old crank seals weren't replaced when the new piston and rings went in. But that's another topic...

Thanks

Had my 25 Johnson since '97 (brand new). Never used anything but the cheap stuff, mostly weedwacker type. Ran like a charm yesterday. Can't believe everything you read.....

New River Rat said:

Had my 25 Johnson since '97 (brand new). Never used anything but the cheap stuff, mostly weedwacker type. Ran like a charm yesterday. Can't believe everything you read.....

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Ding! I love weedwacker oil as well. It's 25 cents at yard sales and it's all forward and backward compatible for air or water cooled if it was made in this century. I scored a gallon of snow mobile oil for a few bucks on clearance. Never understood why the lake did not freeze?