G-several questions

Was running the G a few days ago when I noticed that the ammeter which normally runs a little on the positive side, went to zero. A day later, a post-startup observation showed no movement rather than the normal strong charge and eventual decay. Am putting the batteries on a charger so to avoid freezing. Your thoughts, pls, would you bet on a voltage regulator or a generator problem...or something else. Just looking for the best place to start.

Also, I do not have suitable tightness in the clutch drive disc to crank interface. I notice Dengler's has undersize discs for a G but what dimension (spline major diameter I would guess) is required to establish the proper undersize dimension? The crank seems in pretty good shape; looks that the majority of the slop comes from the disc. What is the correct print dimension of the crank at the spline so I can compare my as-found dimension to it? I have an extra drive disc in fair shape that I was considering trying to shim with some hard steel shim stock; does anyone have experience with that procedure and did they have any luck?

Finally a note on my experiences on G timing, I marked the flywheel to establish degrees BTDC. At 950RPM, the unit starts to smooth out well at about 27-28 degrees. I didn't advance any further to avoid detonation but figure since I burn 93 octane in it, I'm probably safe. Seem reasonable?

Thanks again,

Rob

Mikey G

As far as timing, 20 to 25 advanced is more normal, but as you say, the high octane gas youre running will help reduce pre ignition spak knocking. However, depending upon the load and RPM, that could still be too fast. If you get the static initial starting timing too fast, it gets a little tough at starting and may be hard on the starter drive if she wants to kick back against the starter. If you run a distributor, you can adjust the mechanical advance to accomplish some of your running advance goals without having too much static startign advance. Are you tryign to set up for pulling or something??? Are you running higher than stock compression??

Generator answer is below. Good Luck, let us know. Ol John T Nordhoff in Indiana

I will start with some basic theory type info and hope others will add to it. First, a bad battery can wreak havoc on any charging system, so you might check that using a load tester first. Second, the generator needs a good physical ground connection and the Voltage Regulator needs a good connection to the generators frame and the belt needs to be tight. Of course, it may be possible that the generator is putting out okay, but a short in the system is draining both the battery and the generators output. When not running, if you disconnect and reconnect the batterys ungrounded cable, is there a spark?? If so, post back because that may mean you have a short.

Now, if theres no shorts, the battery is fine, and the Gen and VR are grounded and the belts tight and battery okay, it should read 12.6 volts at the battery, but with the tractor at fast RPM, battery voltage should rise to around 13 to 14 volts or so IF the charging system is working. Even with no voltmeter, the lights or a 12 v test lamp on the battery should grow brighter as RPM is increased.

If the voltage doesn't rise and you’re sure the battery and grounds are all okay, insure the VR's Bat terminal is actually getting to the battery, because it cant ever charge if a wire is off or there’s no connection between the Bat terminal on the VR and the battery itself, maybe through an ammeter if you have one. Place a test lamp on the Bat VR terminal, and it better indicate battery voltage at that point before you go further.

Now, if you have battery voltage at the VR Bat terminal and all grounds are okay and the battery is okay but she wont charge, its time to see if its a VR or generator problem. First, with the tractor running, ground out the Field terminal that’s leading out of the generator and see if she then charges. If so, the VR is bad or there’s a broken connection (like between Fld on Generator and Fld on the VR) or a bad ground somewhere. If she still dont charge, leave that connected and then jump the Bat and Gen (or Arm) terminal on the VR together and see if she charges then. If so, the cutout relay portion in the VR is bad. If still no charge with Bat and Gen (or Arm) connected on the VR, and a good connection between the Gen (or Arm) on the VR and Arm on the generator, and field grounded and battery okay and Bat terminal on the VR is actually connected to battery, it’s looking like a bad generator. A common problem is the brush hold down spring system is corroded and stuck and the brushes arent held tight against the commutator. Other problems are a grounded armature or worn brushes or open field windings. Also, you can remove the generators belt and unconnect the field and then apply battery voltage to the generators armature post to see if she turns (motors), and if she does and then if you ground the field she slows slightly, the generator is usually good. Have you polarized the system lately and has anything been changed as far as positive or negative ground???

The short answers are check for battery voltage at the Bat terminal on the VR, load test the battery, check for shorts, try shorting out the field and try shorting the Bat and Gen (or Arm) on the VR when running and post back.

Theres lots more that could be said to cover every possibility and tell you how to test for each, but this is a start for you. I am planning a two part series of articles in an upcoming Green Magazine issue(s) on this very subject, since its a little complicated to cover on this board. Happy Troubleshooting and let us know what happens.