A good rule of thumb to follow.... do a range check with the engine off.. then do one with the engine running. Your target should be 90% of distance with the engine off.

Aussie.. I thought about the throttle linkage as well... however with it using a plastic arm on the servo it's not metal on metal. Personally I prefer to use plastic linkage with a ball joint on the carb and plastic clevis on the servo. Many use metal linkage with plastic on both ends... that is the key part.