anyone converted a st 3250 to gas tired of it flaming out at low to midrange hard on airframes not to mention 6 flights per gallon of fuel

CH matra, If you want to run gas, buy a gas engine.
However if you insist, $250 for full conversion at CH Electronics, set up and test run. Ignition$175.00 and Walbor pump carb with adapter $60.00. +labor. The ST3250 runs good, but with the bushed rod you will need 10% oil.
Your choice.

thats what i was afraid of too much expense for what is gained

Hey OK.....
I have a ST3000 on my 1/5 decathlon and love it,,,,it has a 28 ounce tank and will fly for 20 plus minutes with fuel to spare....I run 5% which is about $11 a gallon, and am very happy to invest this much for what I get....everything (including carb) is original and would'nt trade it for anything. I use an 18x10 Topflite wood prop (fyi) Engine is very reliable and starts/transitions/and goes full power without any "coughs" or sputters, which is very rare from what I understand....I also use a type "f" glow plug....

i use bryons 10% nitro 10% oil but it still flames out on me at low to midrange i think maybe i leaned out the low end to much to do away with the sputtering will do some more tinkering with it before i junk it