Hello, I have a 2012
M7040 and for some reason, Kubota decided to make the glow plug heating system a totally automatic process. They went to a lot of trouble to install a temperature sending unit switch in the right rear of the engine block, but it does not come on until 32 degrees Fahrenheit.
The Problem: If the engine water temperature is below 32 degrees (whether this is the first start up of the day or the tenth, the glow plug timer will come on which will trip the glow plug energizer relay and the tractor will start right up. If the engine block water temperature is 35 degrees for example, then it almost won't start (very slow and very hard cranking). It's not necessarily a bad battery and it isn't that the cables are bad, it's the fact that the glow plugs have not activated. A terribly short sighted engineering design on the part of the Kubota electrical engineers. They fixed a problem that was not there. On the older manually operated Kubota glow plug systems, you manually rotated the ignition switch to the left until the glow plug indicator came on and then you rotated to the start position and started the engine easily. That is not the case here on the 2012 model.
As an aside, a response to an earlier thread response, the glow plugs do help crank the engine by default. When the cold diesel fuel hits the hot glow plugs, the fuel immediately ignites and the pistons then begin to "push" the crankshaft actually aiding the "push" by the starter motor, thus increasing the speed of rotation, making it much easier for the engine to start.
I have two possible solutions that I would like to run by you guys:
They all have in common a momentary on switch that you can pick up at any boat supplies store or electrical house. It's brass with a black push button in the center. The way that it would work is that you would:
1) mount the momentary on switch in the side of the cowling and run two wires down to the engine block temperature sending switch and then solder the 2 wires to the wiring harness wires just before they connect to the terminals on the temp switch. The wires look very tiny and fragile and they may be very difficult to solder. The system would still retain the automatic function, but could be activated manually as needed.
2)Mount the momentary on switch in the cowling- then remove the cowling and solder the wires on to the timing switch, which would allow the system to remain automatic, but would still be able to be activated as needed. Harder to access the wires under the cowling though.
I realize that there more of possible wiring combinations that would work, but not all glow plugs are the same. They can start at different voltages, and then the voltage can actually be can actually be changed with a variable resistor as it is heating up. This the Kubota Engineers will have worked out and so I would shy away from altering the system there without knowing more particulars.
I would like to hear your ideas on this problem
