I'm surprised Dell didn't respond to this, so I will take the liberty of offering a few of his usual suggestions, although perhaps not quite with his usual style...It only takes a second to check the governor. Start the tractor and grab the throttle rod that goes to the butterfly valve in the carb. Try to move it; you should feel resistance, kind of like when you try to turn a gyroscope in your hand. No resistance? Governor isn't doing its job. Feel resistance? Governor could still have flat spots, weak springs, etc., but is at least trying to do its job. Before dismantling the governor to check for flat spots, etc. (which is time intensive), check fuel flow and spark (which is quick and easy). The INTUITIVE conclusion in these cases is that there must be a carb problem, and there often is; but weak spark will also fail under load. And, it is much faster to check the performance of the ignition system than it is to clean, rebuild and re-adjust the carb. So get an extra spark plug and expand the gap to 3/16". Pull a spark wire from one of the plugs on the motor and pop it onto the 3/16" one. Hold it up against the block (don't worry about the paint). Nice fat blue spark jumping 3/16"? The odds are all the ignition system components common to all four cylinders are ok, although individual cylinders may still be problematic. In this case you can check the fuel flow by pulling the drain plug or the fuel line and checking the stream. You should have a nice, even stream about the same size as the inner diameter of the fuel line. Let it run for several minutes, being sure, of course to catch the gas in a proper container so you can re-use it (hey, U.S.D. 2.79 a gallon!!!). Weak, yellowish spark? RP gave you many of the common causes of weak spark in his reply above; in addition the ignition switch can often cause weak spark even if it tests good with a volt-ohm-meter or test light. Hard to believe, but true.
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