Dave,

Over the past 2 Summers I've been having the same problem with my 63 fz. I took it down to you guys last summer (I live up in Tahoe) but the probem is still there..... Just a refresh of the problem: The engine has less than 2 gallons, Magnum Heli mix, brand new OS f, APC 12/7 filters on both lines, valve clearance is in spec, check valve opperating and tank pressurizes. Engine is incredibly smooth from idle thru wide open (running at 11000 +/- 200)... The problem is still that the engine sputters and dies after 5 or so seconds when you hold the throtle between 1/4 and 1/2, and sometimes above 1/2... It'll run all day at idle and at Wide open.... It dies like hitting the kill switch on a gasoline engine... and trying to open up the throtle while it happens usually makes it choke and die (running too rich kind of choking). I've been all over the board adjusting the regulator screw with the exact same results (except far worse transition charictoristics as expected) Even with the regulator set to make it transition wonderfully it'll still cut out when you hold the throtle between 1/4 and 1/2. I believe you guys put in a new plunger when it was down there at the end of last summer, and the other day was the first time I had run it since I got it back. I checked the plunger, and it looks brand new, and perfectly clean in there.

Hopefully you can help.... I've had this engine in a DP Ultimate 40, and I've only flown the plane about 3 times in the past 2 years (all dead sticks!!) I'm afraid my luck is going to run out on dead sticking it in with out screwing the plane up!!