When I first start my MGT engine it works fine for a minute or so but then my MGT sounds like its in a high rev and even when I let go of the throttle it keeps moving quickly and loudly (all the linkages have been checked and are fine including the idle adjustment). When I hit the brakes the truck does come to a stop but the engine's reving continues. Is my clutch not disengaging or is there another explanation for this problem?

Sounds like tuning...check the low speed might be lean...

could also be the idle.

At first thats what I thought but its not the idle or mixture I have already tried different settings

It sounds like it is too lean if your linkages and idle screw are set properly. If you have richened it up with no change, you probably have an air leak.

Is thsi the stock MGT engine or is this an afterm,arket engine? If it is an aftermarket engine, which one is it? The reason why I ask is beacuse some engines have bad carbs on them and no matter how much RTV you thow at them or how good your tuuning skills are, these engines will leak massive amounts of air and always run away.

Aside from that, try attacking all possible air leaks (replace all lines, the tank, RTV seal the engine, etc.).

It is the stock MGT engine