The startup sequence should be:

1 open needle valve 3-3 1/2 turns

2 fuel tank with 15-35% nitro fuel

3 prime cylinder with a drop or two of fuel

4 attach 1.5 volt battery to glowhead

5 turn engine over with spring/hand/starter

6 fine tune needle valve till the engine is screaming then back of 1/8 turn.

But I'm kind of with Flyingrog here, maybe you need to move the grass - dunno. I mean it sounds like to engine is running until YOU loose control of the model - yes/no?

HTH - Steve B.