Chainsaw Repair

Have been collecting some alternative fuels just to see.

I have e-free 91 octane pump gas mixed 50:1 with Husqvarna XP oil
Tru-Fuel 50:1 e-free
Husqvarna 50:1 e-free
Stihl MotoMix e-free 50:1

I am using a Husqvarna 365 Special w/MM to test.  Saw has been running e-10 89 octane pump gas using Husqvarna XP oil @ 50:1.

What I am noticing is that there is a wide variance in carb adjustment necessary to get the saw running correctly. Saw was initially tuned on the e-10 fuel. Dumped the fuel and ran the saw until it used up the last of the fuel. Put in a quarter tank of Tru-Fuel, saw would barely run. Set the carb back to 1 turn each H/L saw would start and idle but no throttle response. Started opening jets a eighth turn until I got the thing running correctly ended up at L@1.5 and H@1.75.

Started over again using Husqvarna fuel, same process, Left the carb settings alone as were set at end of previous test, would not run just blubber. Went back to 1&1 H/L ended up at L@1 1/8 & H@7/8. I mean normally with a MM saw you have to go a little richer to compensate for the muffler mod, not leaner. Could there actually be that much difference in the fuel? You would think that if the saw were running well you could switch between fuels without that much messing around, otherwise how could they sell this stuff to the average Joe and expect no problems?

No time to do the Stihl MotoMix and e-free pump gas today but will report back tomorrow.

Anyone else seeing this kind of stuff or am I just out of it?

Still don't understand why there are such a big variance in the tuning.

If you do a MM you need to open up the jets a tiny bit to compensate, this is not a fresh MM saw it has been running for about a year and a half.

So when I started the test I left the jets the way they were on e-10 50:1 assuming that the tune would be pretty close, no way, saw would not run worth a chit. So went back to factory specs of 1&1 and went from there. What really frosted me was when I switched to Husqvarna fuel 50:1 assuming again that I would be pretty close, no way. Went back to 1&1 and got completely different results.

I am really perplexed as to how things could vary so widely! The saw belongs to me but I still do not want to toast it trying to figure out what is going on!  I do not believe the saw has some type of fuel delivery problem but I guess I will check it out just to eliminate that!

Could very well be, Rochester New York is around 500ft above sea level. I am going to try the other two types of fuel I have tomorrow, so we will see. I know that non-e gas is a whole different situation in respect to tuning but I did not think it would be that much different from one brand to another.

I would think the E-fuel would have the needles out the most for the air-fuel ratio on ethanol & methanol is close to 7:1

Sounds like the high speed nozzle check valve is blown in the carburetor?