My OS 32 pulses badly on descent from FFF. I have tried both the stock TT muffler and a Century 3033. The high speed needle is set at 1.5 turns out. I just can not seem to get rid of the pulsing. Is this a lean or rich condition on the low end needle?? Any suggestions. My head speed is about 1800 using a TJ pro. This condition occurs either with the gov on or off.

If it is Raptor 30 you have, it has got the Wah wah decease.
It is the oneway bearing cuts in and out during descents.
The easiest way to get rid of wah wah is to install the "constant drive gear"(PV 00379) that is included in the Raptor 50 V2.

Could it also be that the tail rotor drive belt is too tight? I notice a surging, strange noise when I quickly chop the collective, but only since I removed and replaced the tail boom/assembly. The belt seems fairly tight, and when the main rotor is spooling down after engine shutdown, the tail rotor rotates a bit.

I am going to try and move the tail boom in a small amount this afternoon and see if it alleviates the problem.

zaremba dont bother pulling your tail appart... sounds to me like its just too rich lean out your high end needle a few clicks and try again!!