Dave,
My YS63 that was sent in you replaced a bad regulator spring and upgraded it to a new piston in now having problems. You worked on it mid-septmember.

Here is a thread that we talked about it after you fixed it.

http://www.rcuniverse.com/showthread...hreadid=264906

I have ran a little over a 1 1/2 gallon thru it since I got it back from you. I ran a 12x7 prop on it like you said. But I am having mid range and low end problems.

I installed a 13x6APC. It peaks out at 11,400. I have it set to fly at 10,600. But during a flight a couple times per fligth it will, not got to full throttle, it will take about 15 seconds to wind up from 1/4 throttle to full throttle. Once it winds up its fine. I can fly it for another minute or 2 changing throttle positions... Then it happens again.

My idle is inconsistant. I have my throttle where it normal, then sometimes during the flight it will idle high, and then sometimes it just dies.

I thought my glow plug was bad, so I swapped to a new OS "F".
that didn't help. I swapped props, and motor Did this w/ 13x6APC, 13x4W APC, Master Airscrew 12x7

New OS "F" glowplug.
My fuel isn't foaming.
11oz Hayes slimline tank.
Fresh Bryon 20/20 fuel.
My check vavle and fuel tank is holding pressure,
I can let it set there for 3 minutes after the motor shuts down and still have the good "hissing sound" when I take the pressure off of tank.
Running a H9 fuel fiter on setup.
and filter fuel from gallon jug, to fuel pump.

Thanks,
Micheal G..

Open the regulator screw 1/2 turn and see what it does. Sound like it is lean in the midrange.

Let me know,
Dave

To open the regulator you mean by turning it counterclockwise, correct.

Correct!