743 Troubleshooting

[RobPg1967]

Symptoms : Turn key to start engine and get either nothing at all or sometimes a clicking sound. Headlights and horn dont work (fuses and bulbs are good ) What Ive done : Battery is tested and ok I removed the battery - I hooked up the 12v battery charger in place of the battery and the headlights and horn work but the engine does not crank. Then hooked the battery charger directly to the starter and it cranked but very slowly - not enough to start. I purchased the two solenoids that mount on the "L" bracket to the left of the starter. (Ive had glow plug issues recently so I got them both ) Before I put these new solenoids in Im hoping to troubleshoot the problem . Im thinking the starter and starter solenoid thats on the starter are ok and that the 30 dollar solenoids is bad .... whaddya think ?

 

[Tazza]

Easy to check the starter. Install the battery again, use a small jumper cable from the +ve terminal to the small screw on the top of the starter motor. The motor should jump into life. If it doesn't you seem to have a starter solenoid problem (you can replace this part).
Does that make sense?
If it works it seems you have a wiring or ignition switch problem between the instrument panel and the starter solenoid.

 

[RobPg1967]

Easy to check the starter. Install the battery again, use a small jumper cable from the +ve terminal to the small screw on the top of the starter motor. The motor should jump into life. If it doesn't you seem to have a starter solenoid problem (you can replace this part).
Does that make sense?
If it works it seems you have a wiring or ignition switch problem between the instrument panel and the starter solenoid.

Makes sense - I will try that . The ignition is 6 months old. Process of elimination .... I will install both new solenoids since I already bought them and then jump the starter as you suggested. Will let you know how it goes. Thanks ...AGAIN Tazz.

 

[RobPg1967]

Makes sense - I will try that . The ignition is 6 months old. Process of elimination .... I will install both new solenoids since I already bought them and then jump the starter as you suggested. Will let you know how it goes. Thanks ...AGAIN Tazz.

Ran jumper wires as TAZZ suggested and by the way , my service manual says exact same thing. Got nothing at all . Fuses ok Battery ok Battery grounds ok Disconnected the power cables from the starter but kept them hooked together - still no lights- this made me think it was a ground or solenoid problem. Replaced both round solenoids and still nothing - no crank no lights NADA. I used the grinder and clean off the mounting point where the "L" shaped bracket that holds the 2 solenoids attaches to the inner engine compartment wall. Evidently that was the problem... or at least I think this was the problem. I was testing - tugging - and jumping wires all over the place and all at once I had juice. By the way - Bobcat dealer sells these solenoids at $ 30 each The nearby auto parts guy told me he could get the same for $ 15 each but he had to order tham . Also - they looked plastic and Im not sure if they would have worked. This auto parts guy also told me he could get the glow plugs too- we'll see.

 

[Tazza]

Ran jumper wires as TAZZ suggested and by the way , my service manual says exact same thing. Got nothing at all . Fuses ok Battery ok Battery grounds ok Disconnected the power cables from the starter but kept them hooked together - still no lights- this made me think it was a ground or solenoid problem. Replaced both round solenoids and still nothing - no crank no lights NADA. I used the grinder and clean off the mounting point where the "L" shaped bracket that holds the 2 solenoids attaches to the inner engine compartment wall. Evidently that was the problem... or at least I think this was the problem. I was testing - tugging - and jumping wires all over the place and all at once I had juice. By the way - Bobcat dealer sells these solenoids at $ 30 each The nearby auto parts guy told me he could get the same for $ 15 each but he had to order tham . Also - they looked plastic and Im not sure if they would have worked. This auto parts guy also told me he could get the glow plugs too- we'll see.

Earthing around that bracket can be a problem. There should be 2 star washers behind it where the 2 bolts go through. Usually this is more than enough for an earth......
As for power to the starter, did you run it direct to the top part of the motor or just the solenoid on the L bracket? you want it direct to the motor to confirm the motor is working.
Glow plugs are very common, most auto stores will be able to get these at a reasonable price opposed to genuine ones from Bobcat which would probably be the same ones.

 

[RobPg1967]

Earthing around that bracket can be a problem. There should be 2 star washers behind it where the 2 bolts go through. Usually this is more than enough for an earth......
As for power to the starter, did you run it direct to the top part of the motor or just the solenoid on the L bracket? you want it direct to the motor to confirm the motor is working.
Glow plugs are very common, most auto stores will be able to get these at a reasonable price opposed to genuine ones from Bobcat which would probably be the same ones.

On the engine compartment wall where the solenoid "L" bracket attaches - there are two square shaped holes side by side for the bolts but my bracket has only ONE hole- so if its not really cranked tight - the bracket can be moved by hand - Im thinking the last owner fabricated this "L" bracket and only drilled one hole.TO ANSWER YOUR Q: yes I ran jumpers ONLY on the starter itself .She fires right up now.

 

[Tazza]

On the engine compartment wall where the solenoid "L" bracket attaches - there are two square shaped holes side by side for the bolts but my bracket has only ONE hole- so if its not really cranked tight - the bracket can be moved by hand - Im thinking the last owner fabricated this "L" bracket and only drilled one hole.TO ANSWER YOUR Q: yes I ran jumpers ONLY on the starter itself .She fires right up now.

AH HA good. At least you know the starter is good.
The L bracket definatly should have 2 holes. On a machine i re-built i ran an extra earth from the base of the solenoids direct to one of the mounting bolts just to be sure. I had the same sort of problems, it would start some times and refused to others. I was pulling my hair out for days till somehow i worked out the earthing problem, i'm still not too sure how.
One other thing to keep an eye on is the connector under the seat, these can corode and cause all sorts of grief. I have seen a few machines that the previous owner had jumped bad connectors.

 

[RobPg1967]

AH HA good. At least you know the starter is good.
The L bracket definatly should have 2 holes. On a machine i re-built i ran an extra earth from the base of the solenoids direct to one of the mounting bolts just to be sure. I had the same sort of problems, it would start some times and refused to others. I was pulling my hair out for days till somehow i worked out the earthing problem, i'm still not too sure how.
One other thing to keep an eye on is the connector under the seat, these can corode and cause all sorts of grief. I have seen a few machines that the previous owner had jumped bad connectors.

I replaced the operator's seat in the cab a couple years ago .... I didnt see any ground or "earth" wires there actually theres nothing there .... I replaced the seat and the seat rails.