Chris,, I just sent off my Saito Fa.72 to Horizon. They will fix your problem . This one was heating up and acting poorly all of a sudden. I couldn't fix it so I sent it in.

I always remove the muffler, plug and lines. Then clean the engine good. (Makes the service guys happy.) Write a note about what it's doing and remember to add anything you want them to do while it's there. New throttle arm, needle , etc.
Don't forget to add your address , email addy and telephone number to your note.

Send to:
Horizon Hobby, Inc.
ATTN: Saito Services
4105 Fieldstone Road
Champaign, IL 61822