Originally posted this on the Pattern Forum, but definitely more appropriate here.....(Thanks for the PM and suggestion onewasp!)

I have a 140 DZ that has been going through plugs at a rate of 1 every two flights. Went out this weekend and went through 5 plugs! Two weeks ago I went through 3. Both YS and OS F plugs, doesn't seem to matter. The problem seems to have gotten worse since I switched fuels. I used to run Coolpower 30% Heli and recently swicthed to PowerMaster 30% DZ blend. I did burn plugs also with Coolpower, but not like with the PM DZ.

Here are some specifics that may help:

YS 140 DZ
prop: APC 16-12
Plugs used: YS and OS F
Pump setting: 1/2 turn IN (rich) from flush
needle setting: 2 clicks shy (lean) of 2 turns
Static WOT RPM: 8400
Elevation: 5300 ft.

With respect to the needle setting, I do seem to have a funny "double peak", one at the above setting and another at about 2-3/4 turns out. However the richer setting is slightly less in RPM (8200) and feels too rich in flight (loads up during throttle up and leaves a lot of smoke trail)
I have tried to go leaner, but I get detonation and and some banging at the mid-range transition. It really doesn't like to run at anything less than what I have listed. I have heard of others at my altitude running much leaner than this (1 to 1.25 tuns on the needle).

I haven't messed much with the pump....I have run it flush and 1/2 turn IN from flush, where it seems to work a bit better (better transition from idle).

Any suggestions??

Thanks,
-Erik

P.S. Thanks for the comments Troy....I'll send you a PM soon.