The TH .46 is a good and strong engine.

Don't touch the needles out of the box, but DO tighten all of the cap screws on the engine.

Pay particular care to push the carb against the O-Ring when you put the carb in place.

This MUST be tight!

Tighten anything that CAN be tightened, including the needle screw nuts, but be careful not to change the needle's position.

Start up the engine and run at least a full tank of fuel through it.

Then retighten the head cap screws as they WILL loosen after the engine warms up! Careful not to strip the aluminum head by over tightening.

Run a few more tanks of fuel through it then start tuning as directed.


If you set it up properly this engine is easy to tune.

It will feel "stiff" when you take it out of the box. This is normal.