Hi,

So I'm having a bit of a problem breaking in a Dynamite .21 Mach 2 engine.

First I pre-heat the engine to about 100*C, then plug the exhaust and start running the car on the starter box to bring fuel to the carb.

I can see the fuel (mixed with a couple of huge air bobbles) slowly traveling along the fuel line from the tank to the carb, but as soon as the fuel reaches the carb nipple it immediately retreats about 3-4 cm (2 inch) back down the fuel line.

And so it continues, with me alternating between plugging the stinger to get the fuel going and holding the igniter to get the engine going, until suddenly, after about 10-15 minutes of this "procedure", the engine fires and runs.

And then it will run just fine for the intended 3 minutes until I shut it down, wait for it to cool down, and it's time to try to start it again... and we're back to square one.

I completely drained the starter box battery (4S 3300 MAh) and glow igniter (1800MAh) managing only three rounds of break-in!

Along the way I have shortened the fuel/pressure lines to an absolute minimum, I have swapped in new fuel/pressure lines a couple of times and I have swapped in an old tank I had laying around. None of these things helped. There are several huge air bobbles in the fuel line and this strange "retreating effect" when the fuel is just about to reach the carb. And then suddenly the engine runs just fine?!

Has anyone got an idea what's going on? Thanks!