The adjustment is the threaded rod sticking out of the back of the injection pump with a lock nut on it. It has a cap on it that is safety wired. cut the safety wire, (if you bought from a dealer ask if it voids warrenty) remove the cap, and hold the screw with a screwdriver when you break the lock nut loose so you don't move the screw when you turn the lock nut (kind of like adjusting the valves) You need to make small adjustments like 1/4 turn at a time. This screw adjusts the amount of displacement that your injection pump pistons have so you are actually metering how much fuel your injector will put in under max load. Be careful and do not go gonzo just because you are still getting more power because if you go too far you can add too much heat into the engine.
you will notice a difference in the rev up speed if it was out of adjustment. You should see a small amount of black smoke on a hard rev. if your rev is really sluggish and there is no smoke it would seem you could get a bit more power from adding more fuel. If you are driving your tractor in 4th gear on the road and needing more than 1/2 throttle on flat ground i would think you are under powered. Mine i actually had to down shift to 2nd gear on a moderate hill on an asphalt road!!! now i just floor it and power up it in 4th gear.
I estimate my HP was set at not much more than 30hp from the factory. This also greatly helped my starting performance in cold weather but then again , mine was really out of adjustment.
While cruising down the road in 4th gear at 3/4 rpm range you should see a little black smoke if you suddenly floor the pedal and then the smoke should go away as it starts to respond. Mine was just not responding to this, and if i hit a small hill and didnt down shift my rpm's would drop from lack of power and i could lug it down to 1200rpm and there still was no black smoke. The engine was starving.
I cannot believe it was that far out of adjustment and all i can think is that the pump they put on mine was pre-adjusted for a smaller HP engine. Not that that would ever happen in china /forums/images/graemlins/wink.gif
Keep in mind that this adjustment only affects the power when the engine is under load. this is adjusting the maximum amount of fuel your engine will get so you will not notice any difference at low throttle or idle.
