Hi Josh!

Sounds like you have too thin fuel lines. No carb mods needed.

Inner diameter must be 3 mm minimum. 2,5mm or 3/32 inches is not enough, ask me how I know .

If the fuel system is made well, you don't need inflight mixture control. It's the easiest glow engine I've ever used.

My setup is following

OS 91 VRDF
Bolly DF91B pipe
McCoy MC9 plug
Ramtec fan
pitot pressure
Sullivan saddle tanks plumbed in parallel
normal hopper tank 100 ml
fuel and pressure lines inside diameter 3mm
Fuel: 80% methanol 20% Aerosave, no nitro.