I have a Question. I installed a dle-55 on a carden yak 89". i have about 2 gallons of 32:1 lawnboy ashless mixture through it. i also put a velocity stack on it. Problem is, when flying around, 1/2 or full throttle, the engine seems to backfire, i mean it really seems more than a simple burble. it has not stalled yet but sounds like it is real close when it does this. it does it in level flight, vertical, inverted, pretty much anytime and almost all the time. does any one have any ideas about what may be going on ? my first dle-55 is on a gp cap 27% and never had an issue like this, just smooth running. please help.