High Speed...2 stroke...FLAMEOUT...Why?
 

I noticed tonight while making downwind high speed runs with the Magnum that after the diving turn as soon as the plane leveled out at top speed the engine would hesitate or "burp" as I call it.[&:] The first time it did it I thought the tank was letting me know it was about empty so I landed immediately. Wrong....the tank was 6 or 7 cranks from empty. Went up again....same thing.....longer hesitation.[&:] Chopped the throttle to land again and that dreaded sound of silence after the scream of a tuned pipe. Barely made it back to the runway, but down safe and sound. The tank was again 6 to 8 cranks from empty.[:@] Set up is a ST 45ABC Perry (1400) carb, Mac's header and pipe tuned to 16,500 with a 9x7 APC Sport. The tank is a 7.5 oz stock setup that came with the Magnum. What is causing the momentary high speed "burp," flameout. It gives me the willies when it happens cause I'm running downwind full speed halfway down the runway and low no place for a flameout.[:'(]

I just remembered something I read on Mac's Pipe site about a pressure spike that can occure on a high speed power dive where the engine outruns the tuning. I guess I'll call them tomorrow and see how to correct it.

RE: High Speed...2 stroke...FLAMEOUT...Why?
 

Make sure the pressure nipple isn't clogged.
My Webra .50 can out run the fuel system with stock muffler pressure. It runs best with an open header, no pressure tap.....with the needle backed out to compensate. If you want consistancy and speed, set the engine up with a control line style venturi and crankcase pressure.

RE: High Speed...2 stroke...FLAMEOUT...Why?
 

Hi!
Use the tank we use in pylon racing! A Tettra "Bubbleless"!

RE: High Speed...2 stroke...FLAMEOUT...Why?
 

Installed a Jett 8oz bubbleless today.....also called Mac's who was very helpful. Gonna try the tank first then shorten the pipe just a tad if that doesn't work. Couldn't fly today to much wind. Mac's thinks I'm takin it to the limit on the ground "static air", which is taking it beyond its limit in the air at the bottom of the dive. Makes sense!!! This whole speed thing is new to me but I'm learning.......;)