Fuel additives for better performance?

[woodshave]

I recently had my Stihl 090 out on a 95 degree day and it vapor locked within 5 minutes. It took a long time to cool off in order to restart.

My suspicions are that the high ethanol content, coupled with a slight vacuum in high temperatures made it ripe for the vapor lock.

I'm using fresh premium gas from the local pump with Stihl mix oil. This is the same gas that knocks regularly in our daily driver.

Is there any additive I can use to cut down on the volatility of the gas and aid in power like some of the automotive "octane boosters"? ....that won't hurt the saw?

 

[Motorsen]

Vapor pressure!

Your problem is not directly related to ethanol. But have to do with the vapor pressure of the fuel used. In the winter on the norhtern hemisphere it's necesary to have a higher volatility of the fuel used the colder it gets in order to have the engine igniting on a cold morning. Or even to have the engine run properly in the cold.
On the other hand in the summer you need a fuel with lower volatility to avod the problem you see. Some engines are more prone to vaporlock than others. Depends om the construction of the engine. Some engines heat the carburator and or fueltank more then others. I do not know the big Stihl my self. Allthough it would be great to run one some day to feel the raw power.
Dump your fuel and get some fresh from a gas station known to have a lot of costumers to obtain "summer" grade fuel.
Or even better some SEF of a good known brand. Aspen, VP SEF94 or something of same quality instead of the gasstation junk.

Regards

Motorsen

 

[Motorsen]

Hmmm

This one is on me! You pretty much answered your question your self. I just didn't read your post before answering. Sorry there man.:bang:
But I wouldn't search for an additive for this problem. But I would look for a proper fuel!

Cheers

Motorsen

 

[Mad Professor]

100ll

 

[Nitroman]

100ll

Ditto.

 

[Rudedog]

100ll

Is that for any saw or just the big saws?

 

[Miles86]

If you use pump gas (premium hopefully), try Blendzall 485 (Gold Label) castor/octane booster. It really does work. It contains 5 oz. of castor #460 per pint. Mixes 1 pint per gallon = ~ 25:1 gas / oil ratio, no need for any other oil. It's about $60.00 for 12 pints.

 

[Johny Utah]

Is that for any saw or just the big saws?

You can run that in any gasoline fueled engine. All 100LL is is leaded gasoline that's ethanol free and is 100 octane rated. It's a little more technical then that but you get the idea.