YM 1700 charging issue

[Missouri Dave]

I've been having a charging issue with my 1700 for a while. I thought I had the problem fixed when I found a broken wire in the original mechanical voltage regultor. I replaced it with a solid state version from Hoye. The voltage gauge would bounce around from 5 volts to 15 volts 100+ per minute. I figured that the alternator was bad,took it to a shop to have it rebuilt, they opened it up, cleaned and inspected it, didn't find anything (brushes and contacted looked good), reassembled it, and tested it. It was putting out 15 volts and 10 amps. They thought it might be an issue with the voltage regulator, so I installed a new voltage regulator (1972 Datsun 510). When I started the tractor, at 1000 rpm the voltage gauge showed 13-13.5 volts and rock steady. When I increased the rpms it remained steady at 13-13.5 volts until the rpms were over 1500 all the way up to 2100, then it started bouncing around like before, after 15 minutes the volt gauge was bouncing between 5-10 volts 100 times per minute, when I decreased rpms to 1500 and below, it again showed 13-13.5 volts. Any suggestions?

Thanks, Dave

 

[Clint S]

Did you check the voltage with a meter? Do that an verify that you actually have an issue. Could be a bad gauge or wiring to gauge that "vibrates" a bit more at higher RPMS.

 

[deerseeker001]

Welcome from Wisconsin

 

[Missouri Dave]

Did you check the voltage with a meter? Do that an verify that you actually have an issue. Could be a bad gauge or wiring to gauge that "vibrates" a bit more at higher RPMS.

I haven't varified the voltage, but as consistant as the voltmeter is when the rpms are below 1500, I didn't think that was a problem. One of the reasons I thought that the alternator was the problem was that the tractor would turn over easily after it had been used, but recently the battery didn't seem to charge, if I use a charger after I've used the tractor, the charger shows that the battery wasn't fully charged. After I charge the battery it will show a full charge after sitting for longer than 3 weeks and turns over easily.

 

[Clint S]

Don't take anything for granted with electrical. You need to check the voltage with a volt meter and confirm what you know. I would hate for you to keep throwing parts at it. Check the voltage at the Alt, voltage reg, battery and the gauge. When they checked the Alt did they vary the RPM. I have had more than one Alt charge at lower RPMS and not charge at higher. IF the alt is good and IF the reg is good what's left, wiring or gauge right. Shot in the dark too is a slipping belt at higher RPMS

 

[Missouri Dave]

Don't take anything for granted with electrical. You need to check the voltage with a volt meter and confirm what you know. I would hate for you to keep throwing parts at it. Check the voltage at the Alt, voltage reg, battery and the gauge. When they checked the Alt did they vary the RPM. I have had more than one Alt charge at lower RPMS and not charge at higher. IF the alt is good and IF the reg is good what's left, wiring or gauge right. Shot in the dark too is a slipping belt at higher RPMS

Yes, the shop did vary the rpms, and the ouput was very consistant. I will check the voltage at the points that you recommend. I was going to pull the alternator and voltage regulator and take them both to the shop and have them checked together to eleiminate a problem with those pieces, that would then leave the wiring as a suspect, which could easily be aproblem in a 40 year old tractor. Thanks for your feedback.

 

[Coyote machine]

Check your chassis ground cable to the battery. They often fail internally. Cut back the insulation near the chassis enough to see if the wire is pink or copper color. Any sign of corrosion replace the entire cable. Make sure all battery connections are clean and tight. If those items are exactly as described, take the battery and load test it, and specific gravity per cell. If it's weak replace it. Wiring to/from battery, battery, then everything else in the charging circuit including any fuses, all wiring connections to/from each component. Then the components, V-reg and alternator, starter and ignition circuit. Methodical, one step at a time- no jumping to conclusions. Verify each with VOM.