Yamaha G9 Electrical Issues

[rcgroves]

I have been chasing my tail on this cart and cannot seem to pinpoint my issue.

Cart is a 1995 Yamaha G9

The cart sputters and will run but poorly. I can move it around but sometimes not at all. I have had moments where I can drive it over 300ft with no issues across all throttle positions.

Engine has just been rebuilt and is currently being gravity fed to ensure fuel delivery. It has 195lbs compression, valves are perfect, new carb, all gaskets etc. Timing is on and I believe this is purely an electrical issue.

So far I have checked ALL wiring on the cart. The I replaced the voltage regulator with no changes. I removed starter generator and performed the tests found on this forum and it passed with flying colors. By brushes also look to be in great condition. Wires between the voltage regulator and starter generator have continuity.

The battery is NOT charging. Voltage drops when pedal is depressed and never returns when engine is on even if it is at a high rmp. There is always load on the battery, it never charges.

Tonight I found that I have a little resistance between the two wires on my starter solenoid/relay(1.03Ohms). I do not believe I should see any continuity on these wires. After checking all wiring and going switch by switch and seeing if I can get to zero continuity I found that the only way to achieve this was to unplug the dreaded ignitor.

I have planned on doing the Chrysler ignition conversion but was wanting to get it charging first. Now I am thinking that this may be all the ignitor.

Please see my attached picture showing exactly what I am referring to.

Any input would be greatly appreciated!

https://ibb.co/sqKnrD0

[CP241]

Sounds like the solenoid may be bad. Disconnect everything from it and recheck. The 2 small terminals should be 6.3-7.7 ohms. 1.03 is too low

[rcgroves]

Thanks for the help CP241

I have no continuity between the two terminals(small not large) on the solenoid. I believe the solenoid is good as it opens and closes fine.

For my test I have removed the small wires from the solenoid. I am putting my tester between the two small red/white and black wires and I am getting 1.03 Ohms between them which I believe should remain at infinity if the pedal is not depressed. With everything disconnected but the ignitor, the 1.03Ohm remains in the solenoid wires, as soon as the ignitor is unplugged the resistance between the two wires goes to infinity. There is no spec for this in the book as far as I can tell. Is there is a resistance chart for the ignitor I am not aware of?

[CP241]

There is no test in the book for the ignitor except "replace with a known good unit".

I guess I'm having a hard time understanding exactly what you are testing? One terminal of the solenoid should be 12v with pedal.down and key on, and no voltage otherwise. The other side of the solenoid should just be ground.

[rcgroves]

And that is where my issue is. Somehow I have contact between the r/w and ground. The only way I can get the contact to go away is by unplugging the ignitor. I'm going to try the Chrysler conversion tonight or tomorrow and I'll report back.

Thanks

[CP241]

Originally Posted by rcgroves

And that is where my issue is. Somehow I have contact between the r/w and ground. The only way I can get the contact to go away is by unplugging the ignitor. I'm going to try the Chrysler conversion tonight or tomorrow and I'll report back.

Thanks

If unplugging the ignitor makes the continuity disappear, then the ignitor is most likely where the short is located. HEI conversion worked great for me, but I never had an OEM ignitor to begin with on mine. Technically it was "there" but looked like it had spent the last 10 or 15 years in the bottom of a pond. It was removed from the case, full of rust and corrosion and not worth even attempting to plug in...

[sho305]

First thing is put a ngk bprs2 (iirc) plug in it that is size for g16, as recommended by yamaha dealer. If you still have spark problems then likely its ignitor. The ignitor can have problems with the plug or pins, sometimes squeezing the whole thing a little makes it work, sometimes they quit when hot or get strange when hot. Yes you pretty much have to swap it out to find out. They are expensive, then again they last a long time. They do retard the ignition at low rpm. Also look for any wiring issues that is very common. The battery cables and small wires on solenoid, connectors, they like to go bad. Also make sure the airbox is complete and the top is sealed really well, wrap bungees around it if you need or make/buy new straps for it. If not (modded airbox) you have to enlarge the main jet to get them running right usually. They love to foul out the plug if the airbox is not right.