Wont run with R50 mix but runs fine with Stihl Ultra mix :scratching head:

[kielbasa]

this is an easy one...R50 has castor in it, very thick....the viscosity of your premix is too thick and the carb jets have a hard time passing the fuel - you'll run too lean - might be fine in summer months, but as soon as the weather cools off, forget it.
I've been there a dozen times....especially when the neighbors try running any of my castor based premixes in their motocross bikes...
one oil that caught me by surprise was Redline (synthetic), mixed at 40:1 would not run thru the fuel filter in my 026....

 

[Andyshine77]

R50 doesn't have any castor oil in it, Super TechniPlate is 20% castor. The cold weather doesn't effect R50 or Super techniplate.

 

[kielbasa]

yes, you are correct - I must have been thinking about the Super TP.....regardless, R50 isn't recommended oil injection for the same reason - too thick....even though the saw is premix, you'll notice the lean (too lean) running condition running with the thick oil.

 

[Andyshine77]

When mixed with fuel it's the same as any other mix oil, you will never have any lean issues. I've ran R50 in hot and cold temperatures with out any issues, for about two years now. Like with any saw rejetting is required on a regular basis.

 

[tdi-rick]

yes, you are correct - I must have been thinking about the Super TP.....regardless, R50 isn't recommended oil injection for the same reason - too thick....even though the saw is premix, you'll notice the lean (too lean) running condition running with the thick oil.

Really ? People have been using castor based pre-mix oils in saws for a very long time without issue, and all the pre-mix high performance/race oils are a higher viscosity than 'injector' oils, running anywhere between 12 and 20 cSt @ 100*C, whereas injector oils vary between about 6.5 and 8 cSt at the same temp. Even Amsoils Sabre ATP, specifically designed for OPE is 13.5 cSt, almost twice as viscous as most of the injector oils.
As Andy said, when mixed with fuel as a pre-mix at anywhere from 32 to 50:1, the slight change in density doesn't matter and your saw has adjustable jets anyway.

When mixed with fuel it's the same as any other mix oil, you will never have any lean issues. I've ran R50 in hot and cold temperatures with out any issues, for about two years now. Like with any saw rejetting is required on a regular basis.

 

[tdi-rick]

t
[snip]
one oil that caught me by surprise was Redline (synthetic), mixed at 40:1 would not run thru the fuel filter in my 026....

At what temps and which blend ?
I just can't get my head around this, that a batch of pre-mix won't go through a filter ?
Redlines oils are no thicker than the Motul I use, and I've never had a problem with Tillo fuel filters (felt)

At 50:1 you will have 20ml of oil to 1 litre of fuel.
I'll see if I can calculate the viscosity at 20*C of the mix.

 

[kielbasa]

Yes, I understand your points.....find out why R50 isn't recommended for oil injection.
The Redline (I mixed at 40:1) really caught me off guard too - being synthetic and quite thin (easy pouring). I tried the same batch in my brothers little Poulan - same thing. Had to dump the fuel out of both saws since it wouldn't flow. I brought the saw into the house and let it warm up, you'd never know there's a problem, take it back outside, if you could get it running it ran so lean it would still lean bog with the choke on.
But with Blendzall castor, my saw ran great in the winter.

 

[Andyshine77]

Yes, I understand your points.....find out why R50 isn't recommended for oil injection.

Because it's thick, and it doesn't have solvents in it to make it thin like injector oils. R50 is a mix oil, and gasoline is a solvent, now put two and two together. R50 was never intended to be used as an injector oil.

 

[Zero Gravity]

This problem is common in the motorcycle circles. R50 is a heavy duty race oil. when it is used in trail bikes a lot of times the lower performance engines will not tolerate it without a jetting change. I was running it in a KTM 200 and had excessive carbon build up at 40:1. I switched to 50:1 and it was better. Chainsaw oil should not be confused with motorcycle race oils. My observations are that the chain saw oils are much hotter (leaner) than the motorcycle oil. I ride off road and use the 2 once chain saw oil packets as emergency oil. When I use them. I can definitely notice the difference.
ZG

 

[kielbasa]

Because it's thick, and it doesn't have solvents in it to make it thin like injector oils. R50 is a mix oil, and gasoline is a solvent, now put two and two together. R50 was never intended to be used as an injector oil.

correct...the original poster has a fixed jet carb, and I will almost guaranty his problem is too thick of gas/oil mixture, especially in cold weather...

 

[nanuk]

same fuel?

one week ago I bought 5 gallons of Shell V-power and mixed in a pint of R50.
so I dumped it out and put some 50:1 Stihl Ultra mix with 89 octane in it and it fired right up

are you using the same fuel? you don't say what fuel the R50 is mixed in...
is shell V-power the same 89 octane fuel with the stihl?

I'd get some or your 89 octane stuff and mix in R50 and try once more.