Picked up a couple ultra 150s 2001 that have been sitting around for a little while owner claims they both run after charging batteries putting in gas in getting gas to the filter they do both start but there is no throttle response and the engines rev very highly by themselves have to turn the motor off immediately can anybody tell me where to start?

 

I'm a little new to this forum so I may be repeating myself I've seen a number of folks with the ultra 150s that say the same thing about full throttle at startup where do you begin to look what do you look for their WD all of the carburetor parts and everything works properly the plunger inside works it's got to be electrical does anybody know if the electronic dashboard needs to be working 100% to control the rest of the operations of the motor.