Dolmar 5100s died

[huskystihl]

Neither quality nor octane makes much difference for the typical saw. We proved this at the GTG two weeks ago in Indy. The test saw was my 064 with a port 066 topend. Compression is about 150 PSI. The fuels tested were:

1. Sunoco 94 Pump
2. VP C10 100
3. 100LL AvGas
4. 95 Pump - No ethanol

There was only 3 seconds difference in all the fuels. That little amount may simply be operator difference. Just for the record, it was the lowest octane fuel that made the fastest cut time, Sunoco 94. But like you said, this is not a real high compression saw. It might make a difference on a 200 PSI saw, but that's not what most saws out there have.

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Maybe but i've found that my saws idle and have better acceleration as well as cleaner burning with higher octane.

 

[Brian VT]

It might make a difference on a 200 PSI saw, but that's not what most saws out there have.

That's what I've been told (regarding motorcycles). A high-compression engine may need "race" or AV gas.

 

[huskystihl]

Maybe but i've found that my saws idle and have better acceleration as well as cleaner burning with higher octane.

Also wanted to ad that I agree after a certain octane I would assume it becomes overkill. To bad you didn't have a can of 87 around that day to test it out.

 

[blsnelling]

Maybe but i've found that my saws idle and have better acceleration as well as cleaner burning with higher octane.

Myself, as well as others, have found that modern saws idle and throttle response are poorer with 100LL. I have not run the other fuels enough to know how they idle. These fuels were dumped in the saw, purged, retuned, test cut made, and the fuel dumped back out.

 

[blsnelling]

To bad you didn't have a can of 87 around that day to test it out.

I would not have run it. Not only is that below the minimum recommended by Stihl, but the saw is ported. I'm not taking chances with it.

 

[huskystihl]

I would not have run it. Not only is that below the minimum recommended by Stihl, but the saw is ported. I'm not taking chances with it.

I agree. I wouln't run it either I just wanted to see based off dolmars recomendation of 87. I run orange bottle 89 in my outdoor equip and wont even run that in my saws in a pinch.

 

[blsnelling]

I agree. I wouln't run it either I just wanted to see based off dolmars recomendation of 87. I run orange bottle 89 in my outdoor equip and wont even run that in my saws in a pinch.

A agree that would be a fair test for the 5100. If it doesn't need the higher octane, then I suspect you'd see no difference with the higher octane, or higher quality, fuels.

 

[tdi-rick]

Maybe but i've found that my saws idle and have better acceleration as well as cleaner burning with higher octane.

That's what we've fond with our 98 RON (roughly 93-95 AKI) fuel too.
It's all I'll run now in our OPE, mainly for the cleaner burn. (and there's definitely no ethanol in it either)

 

[tdi-rick]

Just dug out my manual for the 64-7900 and it says

"The engine is designed for unleaded regular gasoline with a minimum octane value of 91 ROZ. In case no such fuel is available, you can use fuel with a higher octane value. This will not affect the engine" (my bold)

This is from a NA manual.

 

[tkuhe]

So my less than one year old 5100s has just been diagnosed with a scored cylinder. I am really f'in pissed! I called the shop that I bought it and he is saying that he will try and see if he can get it covered under warranty but will not guarantee anything.
I know for a fact that the saw has had the proper mix fuel put through it.
Really upset about this....
Any advise from anyone?