I have to agree with this....My FTE T-500 would do the same with the small size of the CO2 bottle. It would spool up and while in the transition stage from Propane to Ramp up with Jet-A the engine would hang briefly and die. Charge the propane bottle again and it would complete the start on the second try. A trick that another turbine flier showed me was to prime the propane bottle again during the start sequence but be careful while doing it. To do this safely you'll need a trigger type vavle on your propane fuel source. I did and it worked, but felt uncomfortable about doing it. So I figured that if the PST-600R and the JetCat turbines come with the bigger bottles there's a reason for it. So I switched and it worked. The engine starts on the first try everytime. The thing to realize is that you still will have some gas in the propane bottle while your flying your jet. A potential problem and fuel source for a fire as stated in the owners manual that came with my engine..

Cheers,