Author Topic: Fuel type and tuning differences.  (Read 231 times)

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Offline KilliansRedLeo

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Fuel type and tuning differences.
« on: April 14, 2014, 03:14:37 pm »
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?
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

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Offline 3000 FPS

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Re: Fuel type and tuning differences.
« Reply #1 on: April 14, 2014, 04:21:22 pm »
I was using the 40 to 1 true fuel and went to 91 non ethanol mixed to 32 to 1 using stihl ultra oil.

I retuned a little but nothing dramatic.    That is all I use now.
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Offline KilliansRedLeo

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Re: Fuel type and tuning differences.
« Reply #2 on: April 14, 2014, 05:02:04 pm »
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!
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

Offline 3000 FPS

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Re: Fuel type and tuning differences.
« Reply #3 on: April 14, 2014, 06:51:41 pm »
You know when I was in California close to sea level and I switched from 91 ethanol pump gas over to the 40 to 1 true fuel I had similar problems with the saws idling correctly until I adjusted the jets.     

Maybe it is the ethanol.
PP 505, 475, 445.

Offline KilliansRedLeo

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Re: Fuel type and tuning differences.
« Reply #4 on: April 14, 2014, 08:13:59 pm »
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.
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

Offline KilliansRedLeo

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Re: Fuel type and tuning differences.
« Reply #5 on: April 15, 2014, 07:08:33 pm »
Started over from the beginning but was able to try all four fuel types. Still getting the same types of results. Tuning is all over the board. So, lets try this, if you had a Husqvarna 365 special with a MM and wanted to go with non ethanol pump 91 octane fuel and 50:1, where would you initially set your jets. Factory is 1&1 L&H. I am a pretty conservative guy so I started at 1.75&1.75 H&L.

I just can't understand how there could be that much difference in three different brands on pre mixed non-e canned fuel and non-e pump gas.

Beginning to believe that there is a problem elsewhere, going to pull the carb tomorrow and have a look.
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

Offline 660magnum

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Re: Fuel type and tuning differences.
« Reply #6 on: April 15, 2014, 08:22:54 pm »
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
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Offline KilliansRedLeo

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Re: Fuel type and tuning differences.
« Reply #7 on: April 16, 2014, 11:32:28 am »
OK, I'm at it again! Pulled the carb and pressure tested it for leaks, none. Put a kit in it and tested again, no leaks. Tested the saw for leaks, passed both pressure and vacuum tests. Decided to stay with the Tru-Fuel until I figured what was causing the wide variance, then try other fuels again. Anyway new plug, saw idles and starts, idles at 26-2700. L jet set @ 1.75 turns out. H jet the same for now. Saw will rev then when transferring to high revs 4 stroke heavily at WOT. Pulled the new Bosch plug for a look, gray! OH no, pulled the muffler no damage.

So what do the rest of think is going on? The Gray plug is bothering me a lot!
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

Offline 660magnum

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Re: Fuel type and tuning differences.
« Reply #8 on: April 16, 2014, 11:38:26 am »

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

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Re: Fuel type and tuning differences.
« Reply #9 on: April 16, 2014, 11:47:01 am »
OK, I will give that a look. I have a new carb on hand perhaps I will just switch carbs and see what happens.
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

 

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