Yes, and when run on methanol, they run too cold, and the fuel condenses in the runners... No easy way to heat up the runners... its a common issue with glow 4 stroke engines to get the fuel to vaporize, they would be more fuel efficient.... I tried running the boxer on zero nitro and wasn't too impressed with the performance, so I run it with 8% nitro in the mix.... pulls the 21 pound J3 around with little more than scale like performance, not under powered by any means, but well balanced... not sure if I would attempt to do the gas conversion on that model. just due to the combination of the reduction in performance, and the complexity of re-plumbing the fuel system over to gas... there's a lot of work to get to the fuel lines buried in the wings and fuselage.