G1800 intermittent start

[lakeside]

I'm starting to have a problem with my G1800 with 600 hours on it. I changed the battery, starter and starter switch last year when I started having intermittent starting problems. I finally had enough and took it to the dealer where they found a grounding problem. Things worked will till two weeks ago. I now turn the switch and although I can hear the fuel pump and the glow plug light comes on, nothing happens. I can sometimes turn the switch a few times and the engine then cranks over nicely and starts.

When it happened again over the weekend I opened the hood and left it open which seemed to sometimes work (it seems to have cooled down the engine compartment) I then hooked up a battery charger which showed the battery to be at half. When the battery was fully charged, I turned the key and the engine started.

During running I see 14v at the battery which seems to show the alternator is working. I bought a voltmeter which I'll install next weekend to see if the alternator is consistently charging. I did see the outer insulation on the wire leading from the alternator is chaffed but the inner wires are protected by a wire mesh covering. Could 25 years of service broken a conductor?

I'm also going to install a battery isolation switch to see if that solves the problem, I could be getting some drain on the battery when the engine is shut down.

Any suggestions?

 

[marchanna]

Try connecting the voltmeter from the + terminal on the alternator and then the - to ground. Rev the engine and watch for a voltage drop. This will indicate if your alternator is working properly without the current being buffered by the battery. I would also set the multimeter to save high/low values because sometimes you can’t see the spikes and dips on the display - most modern digital multimeters have this feature.

 

[Kubota3710]

You might also check under the radiator screen under the steering wheel. There is a voltage regulator tucked away under there, right behind the dash. I had the dynamo (basically an alternator) go bad, which then seemed to cause the voltage regulator to fail. Obviously you need about 13-14V coming out regulator to keep the battery charged. I have attached a pic of the voltage regulator check. Basically you do continuity checks with a multi-meter.

 

[lakeside]

You might also check under the radiator screen under the steering wheel. There is a voltage regulator tucked away under there, right behind the dash. I had the dynamo (basically an alternator) go bad, which then seemed to cause the voltage regulator to fail. Obviously you need about 13-14V coming out regulator to keep the battery charged. I have attached a pic of the voltage regulator check. Basically you do continuity checks with a multi-meter. View attachment 560566

It seems like I have a slow draw somewhere which may be causing my intermittent start. If I attach a charger it shows the battery at 50%. When I charge the battery the tractor starts well, so it seems above a certain charge there's enough energy to activate the starter circuit. I'm really at a loss as automotive electrics are not my strong point.

What's got me confused is there will be times when I turn the key and the only that happens is I hear a click. Sometimes, if I continue turning the key off and on, the tractor will suddenly start well.

I did disconnect the cable from negative terminal from the battery and found 13v even when everything is shut down. Is it normal to have any voltage between the negative cable and ground with everything shut down?

 

[Baby Grand]

Check the fusible link. Remove it and measure its resistace while you flex the cable. It should have a constant, very low/immeasurable resistance. Replacement can be had at NAPA for about $5.

 

[lakeside]

I think I solved the problem. I removed the starter and took it to a local starter repair shop last week. They tested the starter and it was working fine.

The tech suggested my problem could be a bad starter relay. He explained the starter relay sends voltage (and amperage) to the solenoid which causes the solenoid to throw the pinion out to engage the ring gear and engage the starter motor. In my case, the amperage was so low that, unless the pinion was in exact alignment with the ring gear teeth, the solenoid didn't have enough force to mesh the gears.

I bought an aftermarket starter solenoid and installed it. Where I would get perhaps one start in ten tries, I'm now getting 100% starts.

Installing the relay was easy.

Bolt the relay to the frame and ensure you get a good ground. Attach a wire from the large starter post to one of the two copper posts on the relay (it doesn't matter which one you use). Attach the second copper post on the relay to the smaller connector on the starter solenoid, the one where wire goes from the starter switch to the starter. Last, attach the existing wire that was going from the starter solenoid to the smaller, third, post on the relay.

All new connections were done with 12 ga wire and automotive crimp connectors.

For safety, anytime I work around a car/tractor electrics. I always remove my watch and rings. I then disconnect the ground wire and secure it well away from the neg post and I always were safety glasses.

I don't want to be preachy but I've already been sprayed with battery acid once in my life and if wasn't for my safety glasses I'd probably be blind.