looking over wiring diagrams for my bobcat 743, I noticed that the glow plug solenoid is activated by the starter solenoid when starting engine? it cuts out when starter is disengaged...is this normal?? this is in addition to being able to activate the glowplugs normally via the ignition switch. Is this common??
Some switches are wired to engage glow plug relay on "half start" which is not cycling key all the way to start. If that makes sense. If you play with the switch you'll see the indicator lamp light up just a hair before the engine actually cranks.
Yes it is very common on small Japanese diesels. You turn the key backwards to preheat the glow plugs for some amount of time, then hit the starter and they stay energized to help it start. Due to the glow/start at the same time, a few of them will start pretty quick even without preheat. But the 743 Bobcat IIRC has a little Kubota which just flat will not start unless preheated a bit. If preheated properly it will start like it was warm.
yes the v1702 is really dependent on glowplugs to kick things off when cold. However im repowering with a v2203. Never the less, previous owner(s) down the line ran into wiring issues and abandoned the whole wiring harness and opted to run a their own set of wires just to the ignition switch. Gauges, idiot lights...any lights...all be dammed. With the motor out, (whole ass end taken apart) now would be a good time to address the wiring issue. If im going to the trouble of repowering...im going to make damn sure i know what the hells going on back there and not overheat and screw up this engine. Along with motor im replacing the radiator and muffler too. Plus a new seat, paint etc.
In Texas you can hook it up any way you want. Preheat the glow plugs then crank without them if that makes your wiring simpler so you don't have to buy a factory switch or whatever. It will still start that way.