It sounds as if you may have an impeller or driveshaft issue. If the impeller, or the impeller housing is badly worn, the craft will loose power due to excessive tolerance between the two parts. This is very common when used in sandy bottom, shallow water conditions, as the sand picked up by the rotating impeller wears away at both the impeller, and the housing. Also, in the case of little, or no service maintenance, the driveshaft splines may be severely worn, due to no grease, at the coupler or the impeller end, causing slippage.
120 full throttle
about 80+ sixth gear full throttle
The motor chokes at full throttle because either the exhaust valves are bad and cause the motor to loose compression at full throttle or the carb has an air leak.
You need to clean out your carb or need a new throttle cable
Your 1987 Astro might go full throttle when the engine is started because the throttle is sticking. This could also be a problem with the starter or the ignition hanging during the start.
If your 2004 Jeep 4.0 engine has cranked up at full throttle, take it to a professional mechanic.
To "take off full blast" means to start quickly. The idiom refers to a motor or jet engine starting off at full blast or full throttle, which would be as fast as possible.
Assuming this is the 4.3 engine, the throttle body would be found on top center of the engine. The air filter assembly would have to be removed to get a full view of the throttle body.
full throttle
Large vacuum leak. Check the hoses that hook to the intake manifold.
It may be that the idle is set at max rpm on your carberator
The canam ds 250 will go up to 51 mph at full throttle.