In you first post you said this is a Thundertiger engine however the link you just posted is for a similar part for a Supertiger engine, which is it? Tower does not sell Thundertiger parts and chances are they are not interchangable.

At any rate look at the picture of the part you posted. See that half moon ground on the shaft? That is where the round boss of the carb rides and that jamb pin cannot be removed in either direction while the carb is still in the engine. Period.

Like I said the nut is loosened and a gentle tap on the hex nut end removes the pressure on the carb and the carb is 'twisted' in the engine not pulled and it will fall out. After the carb is removed the cinch pin will slide right out without ever completely removing the hex nut.

Pounding on either end of the pin or severely tightening it will damage the round part of the carburator boss in addition to the pin and hex nut. I would highly recommend you get some help before you cause any further damage. cinch pins may be cheap to replace but carburators are not.

John