2 Cycle Oil Mixture

jnmeade

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Jim Meade
Is 2 cycle oil such as used in Rotax 503 mixed by volume or weight?
References, please. I've looked all around the internet and not found a definitive statement by an oil or engine manufacture. Lot's of implications and inferences but no definitive reference.
No doubt, many mix it by a bottle of this and a jug of that. (Which implies volume.) Fine. But I'm looking for the oil or engine companies specific spec on how it's mixed.
TIA
 
I thought the 503 had an oil injection pump, negating the need to pre-mix it?

FWIW, my chain-saw manual specifies the mix ratio using volume.
 
I've never seen a 2 stroke mixture that wasn't done by volume. Indeed if you read the manual for the ROTAX, it tells you to mix it by volume.

Oil injection is an option for the 503's. The "base" engine doesn't have it and requires the oil to be pre-mixed with the fuel.
 
Volume. Rotax knows full well pilots don't carry around scales to measure their 2-stroke mix. And for their engines that have oil injection pumps, they work on volume, too.
 
I've never seen a 2 stroke mixture that wasn't done by volume. Indeed if you read the manual for the ROTAX, it tells you to mix it by volume.
.

I read the manual for the 503 before I posted the question and did not see the instruction to mix by volume. I will read it again to find the citation. Thank you.
 
I appreciate the links, very useful.
The manual talks about volume when it comes to the gasoline, but doesn't talk about volume in addressing the oil. I'll accept it is inferred. I like you reference to the measuring cup. That is handy as I have some good oil in larger than the usual small doses.
 
I appreciate the links, very useful.
The manual talks about volume when it comes to the gasoline, but doesn't talk about volume in addressing the oil. I'll accept it is inferred. I like you reference to the measuring cup. That is handy as I have some good oil in larger than the usual small doses.
Yes... volume with both gas and oil. 50:1 mixture = 5 gal of gas and 12.8 oz of oil
 
I like my Rotax snow machine engines. I wonder when the aircraft engines will adopt E-Tec technology. My oil consumption in the E-Tecs is shockingly low.
 
If you mixed by weight the mix would be lean on oil. There are some who mix 2 cycle oil in normal aircraft engines at 1000:1
 
I think it's pretty funny when guys flying behind motors made by sewing machine company dis Rotax as a snowmobile engine.
since the OP was talking about a 503, where was I wrong?

from the rotax page:
1977 – 1989: The peak of ultralight flying and some famous Rotax two-stroke aircraft engines
Based on the Rotax 503 snowmobile engine, the development of the two-stroke, twocylinder certified Rotax 501 and 505 engine, soon equipped with electronic ignition, started in 1977. These engine models were used mainly for motor gliders.
 
Mine is in a self-launch glider, the Taurus in my signature line. Not that it makes any difference. :)
 
I like my Rotax snow machine engines. I wonder when the aircraft engines will adopt E-Tec technology. My oil consumption in the E-Tecs is shockingly low.

I love my Rotax snow mobile engine too, 800 etec, 2015. It has balls. But, I'm not sure I would trust my life in the air to an engine with main bearings lubed by grease and not oil.
 
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