Pump Gas Question

[LM1M]

When running a 602/604 crate, is it ok to run 91 Octane gas (as opposed to the recommended 92)? Is it a must to get gas that is Ethanol free?

[dirtracer_75]

Ive ran Shell 93 pump gas for years in both 602 and 604 crate engines with zero issues. Anything lower octane I really haven't tried.

[LM1M]

Is that Shell 93 Ethanol free? Thanks

[95shaw]

Is that Shell 93 Ethanol free? Thanks

to check for ethanol free, put 2 oz distilled water in a graduated bottle. fill most of the way full and mix well. let stand for a few minutes. if have more than 2 oz water in bottom, likely not ethanol free.

Ethanol makes fuel more likely to vapor lock, especially on restarts. That was the problem I had. I put a return line on carb with a .040 jet in it to help prevent vapor lock. Has worked so far.