HPI Monster Truck ForumTalk about HPI monster trucks here. The infamous Savage 21, SS, .25 or any other HPI MT. You can optionally discuss HPI in our general MT discussion forum if you prefer.
^ That won't help you... This is a common problem with the S-25 carbs, they have an external metal ring that goes on the carb throat, this usually loosens off the carb and becomes stuck inside the engine block. This lets the carb spin around even with the pinch bolt tightened down. Give HPI a call about it and they will replace it for you, I had this and sent in my carb- got a new one back a few weeks later.