I just bought a 743 that won't start without starting fluid. I replaced 3 of the 4 the glow plugs & it still wouldn't start. I checked to see if there is power going to them & I don't see any. What could be the problem & how can I fix it?
They are not automatic you need to hold the key in the correct position for them to be activated. If you are not very careful with the use of starting fluid you can damage the engine. It's been a while since I was in our's or looked at the wiring diagram but I do believe there is a relay on the inside of the frame on the left side of engine looking from the back. If no one fills in the blanks before monday afternoon I'll check at work and give a better answer.
It could be a rocker switch just above the key switch. In either case, once those engines get a little wear on them they will not start without glow plugs. They're a pre-combustion chamber injection engine, not direct injection. No glow plugs, no start.
Don't you have to hold the key switch to the left for 30 seconds for glow before starting?
Yes, or longer, depending on temperature. Ed
Mine was always hard starting.Can't rush the glow plugs,I used to count to 90 before starting it up.One trick I discovered was once it started I would turn key back to glow plug position to keep it running,not sure if this is bad for engine? worked for me.
A lot of machines have a glow plug controller that does keep cycling the plugs at a predetermined duty cycle and time after start depending on temperature... I do not think the 743 does this however, I usually held mine on for 20-30 secs. and it started right up.
Thanks for your responses. I'm getting no power to the glow plugs, but I'm getting power to the pre-heat solenoid, I think that the solenoid is gone so I'm replacing it & I will let you know how it works out!
I have had 4 different Bobcats over the years and the 743 was the hands down the hardest one to start. I agree with L&W, hit the glow plug for around 60-90 seconds then hit start, go back to glow plug as soon as engine hits. It almost always worked for me.
So I've changed the solenoid that powers the glow plugs and they still don't heat up. I can't get my solenoid to send power to the glow plugs at all. One side has power but its not getting the message to send power through to the glow plugs. I took a line & jumped power to the small terminal on the solenoid (the one where the 2 little wires go) & it worked. That means it's not getting the signal. What could be causing the lack of signal?
Those machines have a relatively simple wiring. If it's like the 743B, light blue and black wire from ignition switch goes to the relay that controls the glow plugs. Start at the ignition switch and see if it has power when you turn the switch to the glow plug position. Then check the connector where the cab harness meets the lower frame harness.
ign key to the left to activate the glow plugs, you should hear the glow plug relay click. if you have an aftermarket "fits all" switch i'd start there. if you have an early 743 with the 2 harness connectors INSIDE the cab, thats really good place to check for broken wires :drinkup