Why not use Motorcycle 2-stroke oil in an outboard?

[Nos4r2]

Right, I have a fair idea why not but I've been asked the question and can't provide a definitive answer.
Does anyone have a definitive answer apart from the biodegradable side of it-for both premix and mixing systems?

 

[tommays]

Re: Why not use Motorcycle 2-stroke oil in an outboard?

Long Winter


Tommays

 

[WillyBWright]

Re: Why not use Motorcycle 2-stroke oil in an outboard?

OB oil isn't any more biodegradeable than motorcycle oil. They are made to operate in different temperature ranges, air-cooled vs water-cooled. The only 2-stroke water-cooled motorcycle I am aware of is the old 750 Suzuki Water Buffalo. I suppose there are more, but not many. The vast majority are air cooled. I don't know if they offer separate motorcycle oils for those, but there are so few water-cooled models compared to air-cooled that I'd doubt it.

 

[tashasdaddy]

Re: Why not use Motorcycle 2-stroke oil in an outboard?

the difference in air cooled and water cooled. a motorcycle does not have a thermostat.

 

[Chris1956]

Re: Why not use Motorcycle 2-stroke oil in an outboard?

Willie, I think you are correct on road bikes, but I think all the high performance Moto-X bikes are liquid cooled 2 strokers these days.

 

[ondarvr]

Re: Why not use Motorcycle 2-stroke oil in an outboard?

Yes, all most all current 2 stroke motorcycles are water cooled. Some oils are advertised for use in both applications, but the needs of each can be different.

 

[gss036]

Re: Why not use Motorcycle 2-stroke oil in an outboard?

I would say ash content is the major difference. The standard 2 stroke, "AIR " cooled engine needs better high temperature oil designed for the heat range. AN outboard water cooled engine runs pretty cold when compared to the air cooled engines. My new Husky chain saw manual, specifically says not to use TCW3 outboard oil for it. I use mostly full synthetic M/C racing oil for the saw. That way I know I will have the right type of oil. Most of the lawn and garden shop oils in the small containers are now synthetic, advertised for weed eaters, etc.

 

[Nos4r2]

Re: Why not use Motorcycle 2-stroke oil in an outboard?

Where's The Artist formally Known as LubeDude when ya need him?

 

[seahorse5]

Re: Why not use Motorcycle 2-stroke oil in an outboard?

Outboard motors normallly run for hours at a steady throttle setting. Air cooled 2-stroke motors are usually run at various rpms with very little time at a 'cruise" speed. Look at dirt bikes, jet skis, chain saws, weedwackers, etc.

Air cooled oils have high concentrations of metallic elemets in the additives because of the constantly changing exhaust temperatures. As the air cooled piston varies in rpm, the shrinking and expanding due to temp and load changes help to break off the metallic deposits from the piston crown and blow them out the exhaust ports.

On a constant rpm outboard motor, any buildup of metallic ash can cause a hot-spot and start pre-ignition which will damage an aluminum piston very quickly.

An aircraft engine also has a steady duty cycle like an outboard and the FAA does not allow zinc, a metallic element, in the approved oils because of the chance of pre-ignition due to piston deposits. Now most air-cooled aircraft engines are 4-stroke, but the duty-cycle is similar.

 

[Nos4r2]

Re: Why not use Motorcycle 2-stroke oil in an outboard?

Cheers dude-just what I was looking for.

 

[LubeDude]

Re: Why not use Motorcycle 2-stroke oil in an outboard?

I`m lurking around, but your question was answered correctly.

Now, if the oil doc sees this, he will want to know why I have the authority to even say that!8)

 

[thurps]

Re: Why not use Motorcycle 2-stroke oil in an outboard?

According to Jr. (design engineer Chevron) "There's 2 major types of 2 cycle oil API (American petroleum institute)
grade TC and NMMA TC W3. The w3 needs synthetic in it per the outboard mfg
spec. Though the outboards run cooler, they also run at lower rpm, have no
power valves, and don't cycle throttle position as often so they can gum up
with conventional TC. These facts combined with newer cylinder designs that
cause higher pressures and temps (to keep emissions down) require some fancy
chemistry. anyway, I think the W3 spec was developed after you particular
outboard was made. Bottom line just use the cheapest stuff you can find
that has at least a partial synthetic base and you'll be covered. I think
the dude on the site called seahors5 probably has it about right."