Is the linkage located near the front of the engine where a tab or something could get bent if you ran into a bush etc? Look at the likely places that the linkage could be damaged. maybe something that a carb spring hooks to.

Hey guys, I got some bad news to report on this 9hpVanguard engine. After I got it running right and put the console and switch panel back on, I tried starting it and stopping it repeatedly. I never ran it for more than a few minutes and not under any load to speak of (just spinning the snow thrower blades). All of a sudden I hear this metalic screeching and I shut her down...and following that, she is real hard to turn over, almost cant budge it with the rope pull start. Well it seems like I siezed her up - the 'autopsy' report is that on one occasion, I disassembled/reassembled the carb for a soak in cleaner. Well, on re-assembly, I put the float in upside down and this allowed gas to flood into the carb and overflow into the cylinder, down past the rings and into the sump with the oil. This gas in the oil, caused the oil to lose its lubricating properties and she frooze up. I started up a new thread on the diagnosis and rebuilding of the seized engine over on the tractor forum. I sure appreciate all your help and I am very disappointed that it came to this but I hpoe to turn it into a learning experience. Tim

Here is a little more information that might help clarify the purpose of the diode across the PTO coil (paraphrased from a Wikipedia article): The functional name given to the diode is a 'snubber'. Snubbers are frequently used in electrical systems with an inductive load (PTO coil) where the sudden interruption of current flow often leads to a sharp rise in voltage across the device creating the interruption (the PTO switch). This sharp rise in voltage is a transient and can damage and lead to failure of the controlling device (PTO switch). When the current flowing is DC, a simple rectifier diode is often employed as a snubber. The snubber diode is wired in parallel with an inductive load (such as the PTO coil). The diode is installed so that it does not conduct under normal conditions. When current to the inductive load (PTO coil) is rapidly interrupted (by the PTO switch), a large voltage spike would be produced in the reverse direction (as the inductor (PTO coil) attempts to keep current flowing in the circuit). This spike is known as an "inductive kick". Placing the snubber diode in inverse parallel with the inductive load (PTO coil) allows the current from the inductor to flow through the diode rather than through the switching element (PTO switch), dissipating the energy stored in the inductive load over the series resistance of the inductor (PTO coil) and the (usually much smaller) resistance of the diode. So, this inductive kick does not feed back into ground or into any other part of the engine such as the starter (as mownie correctly mentioned). The potentially damaging energy is dissipated in the series resistance of the diode and the PTO coil.

If you look at my above post, follow the instructions- you will then know if the float valve let fuel into the engine. The float would be attached to the float valve in the carb. You would need to drop the float bowl to access the float. These are plastic floats and typically don't fail. The valve is usually serviced in the kit and you pick the one out of the kit that looks like yours as they don't interchange. BTW, if your oil is diluted w/ fuel- that also mean sthat your cylinder is likely flooded as well. Remove the spark plug and crank with the ignition grounded so a spark from the plug wire won't start the fuel on fire. It is a real good idea to also install an inline shut off valve on these, shutting off the fuel when not in use as these carbs like to fail and flood when sitting. If you had to de-flood the engine- once you change the oil filter and add fresh oil, you may still have oil/ fuel in the exhaust so it will smoke more than normal for the first few minutes.