I'm starting to get back in the R/C world. I've got a HPI RS4 Racer 2 that sat in the garage for 3-4 years and I just now got it running again. It's got a brand new clutch and brand new T15 motor.

Here's my problem:

It's got very unstable idle. It would idle fine at times, sometimes it will idle too high, sometimes it would have an erattic idle. When I brake, it would idle so low that it'll want to shut off. When it idle's low, i'll snap the throttle lightly and it'll idle fine again.

Things i've checked:

I've noticed that I've got alot of slack on the throttle linkage, about 1/8". It'll vary the carb opening alot. Should it have no play at all?
The throttle servo seems to be holding up ok, don't see the gear moving any more than the horn does.
The throttle arm don't seem like it's separating from the carb and the nut is tight. Rotary carb btw.
I've tried to adjusting the throttle linkage longer and shorter.

here are some pictures, don't know if it'll help. These pics were taken with the TX and RX on. any common things? Thanks in advance!