.39 Thunder Tiger quits after about 20 seconds

[MSHeliflyer]

I was wondering why my engine quits after about 20 seconds of running. I switched fuel to cool max but has the same mixture. I have taken out the filter and it still quite. Made sure all of the fuel line connections are hooked up correctly. Also on the glow plug there was a bit of build up and I cleaned it off but still no luck with the engine quiting. Thanks for any advice or solutions.

[tdswan]

If it's idling when it quits, you may be too rich on the low needle. If you're spooling up when it quits, you may be too lean on the high or a comination of the low/high may be too far out of adjustment and the mixture changes too abruptly for the transition. If it's quitting once it's revved up, you may have a fuel delivery issue.

[cbflys]

To add to what TD says...

If it's running at high speed and quits - the fuel deliver issue could be caused by a clogged carburator. Also - check for holes in the tanks / fuel tubing. Pressure test it.

[MSHeliflyer]

yes it is at mid to high engine speeds. How do you clean the carb? Pull the engine out and give it a good wipe down? I have inspected the tubing but not a pressure check, I will try that next. When the engine quits and I get to the heli it looks like there is air in the fuel line where it goes into the engine so I am thining there is an air leak some where. Thanks for all the help and the speed that the replies where posted. This is a great web site and awsome magazine with a lot of useful tips.

HAPPY FLYING!!

[cbflys]

You should not have any air in the lines. That's why your engine is stopping. Probably not the carburetor. Look for pin holes or splits in the fuel lines both inside and outside of the tanks). Again, best to pressure test it. Also - make sure everything is balanced (flywheel, clutch, fan, etc). Excessive vibration can also produce air bubbles in the tank which get sucked into the engine.

[kiwipilot]

Did you replace the clunk line as per the 'online' assembly instructions?

The standard tubing supplied is prone to breaking down and may be allowing air to get in where it shouldn't. This is a common cause of frustration.