plug heat range and flame out.

[mrbones]

Alright fella's, I'm having some flame out issues with my big block motors. I'm running OdDonnells medium range plugs w/25% Byrons fuel. It runs good in all my small engines i.e; 3.3, .18 OS, Novarossi .12's and XTM 24.7 but my big blocks are flaming out when letting off full throttle. (.26 engines). Do I need to be running a cooler plug? Head shims? I've checked the pinch in the big blocks and it looks OK. Do I need to drop down and start running 20% fuel in them?

 

[dub c]

Good question. I think I would try different plugs in the bigger engines. Your using a good quality fuel suitable for any size engine.
It would be helpfull to know under what cercumstance your getting a flame out. IE under accell, after a high speed run...etc

 

[mrbones]

Good question. I think I would try different plugs in the bigger engines. Your using a good quality fuel suitable for any size engine.
It would be helpfull to know under what cercumstance your getting a flame out. IE under accell, after a high speed run...etc

Kind of all the time. After burning across the yard and the braking to turn around and WOT down the street when I let off the throttle to turn around. Even if I'm just putting around the yard and bring it back to me and stop it quits. I'm kind of thinking that my air gap in the carb, my LSN setting, and idle adjustment are not what they should be. I'm sure I have all these settings more than they should be trying to keep it running. This is a Mach .26 and an HPI 25.

 

[dub c]

Sounds like a LSN lean / narrow idle gap