Fuel or Gas for the saws

[esshup]

When running the saws in this hot weather I'm seeing what I think is vapor lock. Only on the smaller of the 2 saws, and only when it's been shut off for 5-10 minutes. But, that's the nature of what I'm doing for the next few weeks so it is what it is. I can't leave it idle all day long.

I realize that I have to be more careful in buying fuel, watching ethanol, etc. I was thinking of solving that problem by either going to the local airport and seeing if I can buy 5 gallons of 100LL or driving another 20 miles and buying Sunoco 260 GT Plus (104 octane).

If given those choices, does it matter much which fuel to buy, or should I just be more diligent in purchasing "premium" pump gas? Right now, I'm going thru about 2-3 gallons per week. Dolmar 7900 and Echo CS340 No mods on either saw.

 

[D&B Mack]

I have run my saws in 100 deg + weather without issue. Have you retuned in the hotter weather. Many times if it is 70's in the morning and hits the century mark in early afternoon, you will need to retune during the day.

 

[2dogs]

Av gas is not recommened in chainsaws. Octane rating has nothing to due with vapor lock, only preignition. If you want better fuel for your saws then run a premixed fuel like 50 Fuel or Stihl Moto Mix. As has been stated you need to tune your saw whenever it needs it. Are you sure your hot starting issue isn't a bad coil?

 

[esshup]

Thanks guys. I doubt it's the coil. The one saw will restart, but dies in 5 sec or so. Starting it on 3/4 choke will get it to run a bit longer. After 6-8 starts like that, to me it appears that it finally pulls fuel thru the system and runs fine. It has a priming bulb, and after it's running (and shut off) the bulb is full of fuel. But when the problem shows up, there is no fuel in the bulb, and no amount of pumping will get it full of fuel.

This is in 90°F and higher temps. No problem in cooler temps. Even waiting until 5-6 p.m. won't do much good, as on those days the temps are still in the 90's. Heck, the other morning at 5:00 a.m. it was 80°F.

Once the saw is running, it runs fine. (at least to these deaf ears)

I'll look into the 50 fuel and Stihl Moto Mix and see if any is available around here.

What specifically is different (in a bad way) if instead of running the saw on 91 octane pump gas I ran the saw on 100LL fuel (100 octane low lead Av gas)? Same synthetic oil mix ratio.

 

[mad murdock]

The 100LL will lead foul the top
End of your engine if used a lot. It is labeled "low lead" but that is in comparison to the other aviation grades of gas that used to be in wide distribution, 100 LL is only low in tetra ethyl lead compared to these fuels. Buy non ethanol premium, you will do fine, but you will probably still need to retune for conditions, as stated in prior post.

 

[Nitroman]

More misinformation about AVgas.

Use it, you'll like it.

Another thing you could do which won't cost you much at all will be to look for the aluminized tape that is used to wrap the joints of stove pipe. Clean up the inside of the cylinder housing and apply the tape so it will reflect heat back at the cylinder and not allow so much radiant heat to bathe the carb housing. A roll should cost you less than three bucks. You'll know the tape because it is like a heavy aluminum foil with sticky on one side.

 

[mad murdock]

More misinformation about AVgas.

Use it, you'll like it.

Another thing you could do which won't cost you much at all will be to look for the aluminized tape that is used to wrap the joints of stove pipe. Clean up the inside of the cylinder housing and apply the tape so it will reflect heat back at the cylinder and not allow so much radiant heat to bathe the carb housing. A roll should cost you less than three bucks. You'll know the tape because it is like a heavy aluminum foil with sticky on one side.

With all due respect, I disagree with your assessment. I have a neighbor who used 100LL in his 044 for years and he experienced just that. 100LL is extremely stable for long term storage and will work in a saw, but if used extensively, will lead foul an engine not designed to use it. Even engines designed for it lead foul, and were it not for 100 hr inspection requirements in aircraft, would lead to more issues. Just my view as a 25+year A&P/IA. I have cleaned thousands of spark plugs in reciprocating aircraft engines of all types. It is just the nature of the beast. With proper and often spark plug maintenance, you will be ok burning AvGas in a saw, but you will run a greater risk of sticking a ring or what have you due to the increased lead in the fuel, if you put a saw on a steady diet of it. To the OP, if all you wanted was to run it during the heat wave, and switch back to "Mogas", then you may not have any issues.

 

[GASoline71]

I got an extra lawn chair if anybody wants to watch... opcorn:

Oh... what's the difference between "gas" and "fuel"??? My knuckledragger brain doesn't compute this...

Gary

 

[2dogs]

I got an extra lawn chair if anybody wants to watch... opcorn:

Oh... what's the difference between "gas" and "fuel"??? My knuckledragger brain doesn't compute this...

Gary

Gas is what comes out of you. Fuel is what we put in our saws.

As an aside my son the Marine ran his dozer out of fuel last week. As a reward he was allowed to drag a 75' long piece of 1 1/8" wire rope with him everywhere he went. All day long.

 

[esshup]

I put both in the title so that someone using the search engine in the future no matter if they used gas or fuel, this thread would pop up. I searched and couldn't find anything, that's why I posted the question.

I'm not trying to stir the pot, it's just that I didn't know the difference between Av gas and unleaded. I'm trying to learn here.

'nother question. What's different about these 2 stroke engines vs. a 4 stroke that these can't be run on leaded gas? I know that lead was added to gas as a lubricant - I started driving and working on motors when leaded gas was the only type of gas sold. The 2-stroke uses the oil as lube in place of the oil stored in the oil pan on a 4-stroke, but why would these saws stick rings with the lead? The '69 Polaris Charger snomobile never stuck a ring.......

I'll know tomorrow if the 100LL does the trick. It's supposed to be 98°F tomorrow.

 

[WoodChuck'r]

When I cut wood I use a chainsaw.

 

[esshup]

2dogs. Good one! I actually put gas in the chainsaws, and fuel in my car (diesel).

 

[Redoakranch]

I started my new 346XP on CA 10% ethanol gas and Stihl Ultra a year ago but switched to 100LL. My saw has ran great on both fuels but I switched when a local dealer said he has seen fuel with 30% ethanol recently and it was pitting the aluminum on brand new saws. I don't run my saws a lot so the 100LL is good for me, not expensive, stores well, and rubber lines are cool with it. I don't mind the fumes, reminds of the races when I was a kid. I was running my saw dry with pump gas to keep the ethanol from sitting in the saw, but I don't like to do that, so I'll deal with lead build up in the future. I had to lean the L an H a bit to run 100LL.

 

[Nitroman]

With all due respect, I disagree with your assessment. I have a neighbor who used 100LL in his 044 for years and he experienced just that. 100LL is extremely stable for long term storage and will work in a saw, but if used extensively, will lead foul an engine not designed to use it. Even engines designed for it lead foul, and were it not for 100 hr inspection requirements in aircraft, would lead to more issues. Just my view as a 25+year A&P/IA. I have cleaned thousands of spark plugs in reciprocating aircraft engines of all types. It is just the nature of the beast. With proper and often spark plug maintenance, you will be ok burning AvGas in a saw, but you will run a greater risk of sticking a ring or what have you due to the increased lead in the fuel, if you put a saw on a steady diet of it. To the OP, if all you wanted was to run it during the heat wave, and switch back to "Mogas", then you may not have any issues.

Only guess I can make about the aircraft engines fouling is them running cool and rich and the really low 6.5:1 compression.

I have run my saws on 100LL exclusively since I've owned saws. I have run thousands of miles up on my 1994 Polaris 440GT, 2007 Arctic Cat 570 Bearcat, an Evinrude 88HP outboard and a Johnson 175 HP (jet unit) using AVgas. I have never had any problems. When it is really cold I might need to pull the starter on the snogo's a few more times but they run excellent, smoothly, and smell good too. Same with the saws. Only thing better is running the saws with castor.

 

[Rudolf73]

I use gas in my barbie (BBQ) and then throw some shrimp on it :msp_wink:

 

[Tzed250]

Gasoline can be a fuel, but fuel does not have to be gasoline. Motomix is not even advertised as gasoline, it is called a fuel.

When you say fuel to a drag racer, they immediately think CH3NO2

 

[WoodChuck'r]

Gasoline can be a fuel, but fuel does not have to be gasoline. Motomix is not even advertised as gasoline, it is called a fuel.

When you say fuel to a drag racer, they immediately think CH3NO2

I just ate a toasted bagel with cream cheese. I like to call it fuel. I also need to get to Lowes to buy some lumber to repair the porch steps. They're getting worse as the years go by.....

Grape juice tastes good. Hi John.

 

[Tzed250]

I just ate a toasted bagel with cream cheese. I like to call it fuel. I also need to get to Lowes to buy some lumber to repair the porch steps. They're getting worse as the years go by.....

Grape juice tastes good. Hi John.

The Chuckster strikes again!!

BTW, +1 on the grape juice!

 

[Nitroman]

I use gas in my barbie (BBQ) and then throw some shrimp on it :msp_wink:

But you can get away with that due to you being Aussie. Non-Aussie's...I think there is a law against that somewhere. I think.:msp_biggrin:

 

[Rudolf73]

But you can get away with that due to you being Aussie. Non-Aussie's...I think there is a law against that somewhere. I think.:msp_biggrin:

Yes I should have clarified - I use 'propane' gas. I think that's what you call it.