Thats what I was looking at, the throttle system has been defo tampered with as originally was an idle cut out set up when you let go of trigger, tried different nozzles in, including a size 15 and still bogs, if it was partially blocked would the unloader not compensate and dump back to tank? i'm thinking you may be right with the govener idea, I have even checked to see if any throttle / stop cables are catching any where when the trigger is pulled... nothing, seems fine, had a play with the throttle cable when under load, still no joy, throttle is open to the max, I'm not familiar at all with these engines, have you ever worked on one carl? would be good to have a chat if your free any time?
