(quoted from post at 23:59:54 04/02/11)
Question: should the rockshaft/linkage that goes to the carburetor move back and forth when I move the engine speed control at the operators platform. I mean, does it move back and forth when I advance/retard the throttle control while it isn't hooked to the carburetor.
It usually does, but if the governor is not set correctly it won't. There are several conditions that can cause these symptoms. I wouldn't jump on any assumptions. Here are a few diagnostics:
[b:4dd773711b]The governor travel adjustment screws are too tight.[/b:4dd773711b]
The governor screw adjusts the maximum mechanical travel to keep from damaging the carburator. But if adjusted too tight, it can keep the carb linkage from moving sufficiently. Too loose and it can damage the carburator. With the engine "off", remove the rockshaft bracket and shaft. Do not lose the key on the end of the shaft when the shaft is pulled out of the governor. Use a flashlight and watch carefully. Back out the screws and count the number of turns while watching the governor cross shaft keyway for rotation. If there is rotation continue backing the screw out until the rotation stops. Set the governor throttle control up by the steering wheel to the idle position. [b:4dd773711b]"CAREFULLY"[/b:4dd773711b] start the engine and [b:4dd773711b]manually[/b:4dd773711b] control the engine RPM with the throttle on the side of the carburator. Do NOT allow the engine RPM to high rev, keep it at a slow Idle. With a flashlight, watch the governor cross shaft socket on the side of the governor. Slowly increase the engine RPM and watch to see if the governor rotates clockwise in an attempt to close the carb throttle. If this is working, the governor is NOT the problem. Set the travel adjustment screw to just a little less than the travel needed for the carburator open-to-close travel needed. With the engine off, set the carb control rod length to fully open the throttle. Now when the engine starts, the governor will close the throttle to the idle RPM.
[b:4dd773711b]The rockshaft linkage to the carburator may be adjusted too short. [/b:4dd773711b]
This assumes that the governor maximum travel screw is adjusted properly (i.e. control shaft moves back and forth just enough to open and close the throttle). With the engine "off", adjust the carb linkage out enough to open the throttle wide open. As the engine starts and begins to rotate the governor weights, they will pull the rod and try to slow the engine down. Moving the throttle applies extra force to counter the force of the weights to allow the engine to increase in RPM.
[b:4dd773711b]The governor rockshaft keyway has too much slop.[/b:4dd773711b]
With the engine "off", Disconnect the control rod from the carburator. Gently rotate the rockshaft back and forth while using a flashlight to observe the insertion point into the governor keyed opening. If there is significant slop, unbolt the rockshaft assembly and simply pull the shaft out of the governor (do not lose the shaft key). Look for damage. You can replace the key stock if deformed, beef up the keyway with shim stock like a piece of hacksaw blade, or use locktight if the slop is excessive. You can break the bond of the locktight in the future by heating the shaft up with a torch. Be sure to use the rockshaft bracket in its final bolted position to align the shaft before the locktight sets up. Recalibrate the governor system since there will no longer be any slop.
[b:4dd773711b]External spring and control arm on governor that connects to the throttle by the steering wheel is frozen.[/b:4dd773711b]
Rust can cause the control arm to freeze up and so the throttle input does not cause a change in RPM. Use penetrating oil and loosen up the throttle input assembly until it rotates smoothly under the spring pressure. Apply some grease to keep the assembly lubed.
Only if the travel screw adjustments allow for maximum movement, AND the throttle input assembly moves freely, AND a change in RPM (slow idle to mid RPM) does NOT cause a governor rotation with the cross shaft disconnected, would I consider the rebuild of a governor.