750 combine question

There is a fuse on a "Grey" cab 750 in the fuse block below the operator controls. There are two temperature senders one for the guage and one for the murphy shut down. When the temperature rises above the hot temp threshold the sender grounds the input to the monitor and in turn the monitor grounds the output through the over ride switch to the overide relay. The relay secondarys are closed when the ignition switch is off. When the ignition switch is turned on (engine not running)current flows to the over ride relay primary side the other primary side of the the overide relay is grounded through the oil pressure sender(because there is no oil pressure), you should be able to here the relay click, which actuaaly opens the secondary contact going to the fuel solenoid. At this point there will be no current to the fuel solenoid. If you hold the over ride switch on the monitor you should be able to here the over ride relay click again (engine not running) which removes the ground from the relay causing the relay secondaries to close, know you should have current ot the solenoid. This sounds complicated, but remember the over ride relay secondaries are closed when the ignition switch is off but ther is no current to fuel solemoid because the is also no current to the secondary of the relay. The engine won"t get fuel until there is 2-3 lbs. of oil pressure, unless you hold the overide relay. There is also an oil pressure switch with two spades on it. This switch turns on the the main relay for the alternator and instruments. On the "Red" cab machines with no monitor the two spade switch actually turns on the the main relay and the fuel solenoid, I"m guessing that is what you have the manual for. I would suspect a bad over ride relay or connection. The relay is located under the panel by the main fuse block.

Tom Dold
Dold Implement
201 S. Main St.
PO Box 70
Howard, SD 57349 605-772-4541
[email protected]

Bud