I have a Craftsman DYT4000 riding lawn mower that I've been trying to revive. I had the mower fixed, or so I thought when the engine starting surging when in high speed, blades off. I had put a new carburetor on, as the mower was missing one when i acquired it, so I started by messing with idle and gas screws on it. I adjusted the governor shaft, thinking it was a governor issue, and the surging stopped. However upon starting, the engine immediately runs wild. Around this point I blew a head gasket and replaced. I've adjusted the governor shaft correctly, as it only has one way it should be turned otherwise you won't be able to move the governor arm at all (governor lever pushes up against the counterweight inside the engine block). When adjusting the governor shaft, i made sure to have the choke in wide open and the governor arm pushed to its position in this speed (all the way to the back of the block). I did open up the engine block to inspect the governor gear. Its not damaged in any way. All of the gear teeth are present and the wheel weights and pin operate as they should when spinning. I've also verified that the throttle butterfly is not loose, and none of the screws have come out of it. It moves back and forth as it should.
I took a video that I'll try and include here showing when i start the engine at the time of this posting. I start the engine and immediately it starts to race, so i move the choke to low speed. I try and move the governor arm while the engine is running, effectively trying to throttle the engine manually, but the arm will not move. I then move the choke to high speed, and the governor arm is still unmovable. Now when the engine is not running, the governor arm moves just fine.
The only thing I could think it would be is maybe there is an air leak where air is getting into the intake manifold behind the throttle, or really anywhere before the cylinder. Now that I'm typing up this post, perhaps the governor is operating as expected and what I saw in the video was the governor pushing the arm all the way to the left (or closing the throttle butterfly) and the arm couldn't be moved anymore in that direction.
Any ideas?
I took a video that I'll try and include here showing when i start the engine at the time of this posting. I start the engine and immediately it starts to race, so i move the choke to low speed. I try and move the governor arm while the engine is running, effectively trying to throttle the engine manually, but the arm will not move. I then move the choke to high speed, and the governor arm is still unmovable. Now when the engine is not running, the governor arm moves just fine.
The only thing I could think it would be is maybe there is an air leak where air is getting into the intake manifold behind the throttle, or really anywhere before the cylinder. Now that I'm typing up this post, perhaps the governor is operating as expected and what I saw in the video was the governor pushing the arm all the way to the left (or closing the throttle butterfly) and the arm couldn't be moved anymore in that direction.
Any ideas?
