vapor lock

[Stumper]

I find that using premium fuel virtually eliminates vapor lock problems. Someone on here 'explained' last year that this is due to a differing "10% rate" as opposed to a higher octane rating. I don't much care- so long as it works. Thus far, in every location I've tried it, the premium (but not oxygenated) fuels have worked to prevent hot weather vapor lock.

 

[tony marks]

rocky, its my guess that, that 346 modified is gonna breath alrite
no matter how hot.by the way ,guess what, im gonna take a shot at modifying a saw.think ill start with the little craftsman.
i know the basics so itll be an hunt an peck deal. to see what works.nothin ventured nothin gained.later now.

 

[a_lopa]

ive also found running saws on premium to be the best bet.

 

[bvaught]

The best quality in a fuel to prevent vapor lock is one with a low vapor pressure. You guessed it!!! Aviation Fuel is the best you can buy for vapor lock prevention. Can you imagine a turbocharged airplane at 25 thousand feet getting gas vapor in their fuel line? Or even worse a tightly cowled twin coming in to land on one engine(at full power) and the gas line that is routed to each cylinder (through that hot engine compartment) getting vapor lock?

 

[Bob Wright]

Vapor lock is also caused by hot gas, like boiling in the summertime. Some small saws don't have enough bar oil between the oil tank and the gas tank. Then the gas gets hot. I know this is true on the 1970's Echo's. Boiled gas in all of mine. Then the saw won't run on the hot mixture...Bob

 

[bvaught]

Vapor lock is also caused by hot gas, like boiling in the summertime. Some small saws don't have enough bar oil between the oil tank and the gas tank. Then the gas gets hot. I know this is true on the 1970's Echo's. Boiled gas in all of mine. Then the saw won't run on the hot mixture...Bob

Thats what I was trying to say above. Avgas mitigates this effect, but it isnt totally immune to this problem.

 

[Bob Wright]

Thats one thing we have to watch when we make the gas is the vapor pressure if its off spec we can't sell the gas. Then it has to be reblended...Bob