69 GT14 trans problem ?

[baerpath 517]

Just getting a 69 GT14 around to sell. Having a problem with the hydro. Some times it gets in a rush and does decent wheely's.  Not all the time usually after running it a while. Mowed with it for 1/2hr and then did hill climbing to check the hydro, worked fine. Drove it to the shed and stopped at half throttle when starting to go forward it hesitated and then took off and lifted the front 6 inches a couple of times.  I have to adjust the neutral stop for the pedal also.  

 Just wondering if it could be a sticking valve or more serious. Don't want the kid to have trouble.  Any thoughts ?

[baerpath 517]

Found the problem, PO replaced the idler pulley with one a half inch smaller. So sometimes it would work perfect others not so well. Replaced it with the larger one and it works perfect. Good to have spares to compare to lol