while dyno testing the 520 we are reading 24hp at rated rpm. i noticed that the throttle shaft is not wide open.so we pull the dyno down to lug the engine and the throttle does not open anymore. If I move throttle shaft manually to wide open I pull 31hp. Also the govenor leaf spring adjustment rod is adjusted all the way up the rod to as tight as it can adjust. I have also turned the load screw out several turns and still get no change on hp or any black smoke. It runs like a watch and 31hp would be acceptable for this tractors condition. why is the govenor not moving carb to wide open throttle under heavy load? could the govenor leaf spring be week over time and give problems? Float height is set at 1/2" with a fuel level tube, book says 3/4". Valves are set at .021 cold, book says .020 hot. This is the first run after a complete valve job.
anybody have an ideas?
anybody have an ideas?