Did that engine even come up to temp? Mine needs to be run for a good 1-2 minutes before the first flight of the day.


The GMS 1.20's run well, but getting the mid-range right is a bit of a bear because the engine changes a bit in characteristic over time until it is broken in fully.

I kept getting mid range cut-outs and hesitations on mine until I leaned the low end a bit MORE than you would using standard tuning practices, and likewise richened the high end a bit more than usual.

This cured the mid range transition.

You know you have the engine in the right range when the head temp hovers around 300 degrees at full throttle.

Much higher than that and you ARE going to have problems.

Lower than 280 and it's running too rich.

A laser temp guage makes it easy to tune up the GMS engines... w/o one, the instructions and standard tuning proceedures seem to produce mis-tuned engines.