'94 Yamaha G9 Gas - No Start

[raenglehart]

Hey guys. I've been doing a lot of reading from your site here since acquiring a 1994 Yamaha G9 cart. It seems to have an intermitent "ghost" problem. I'll try to be brief.

Sometimes it just won't start. I have read and tried many things found on this site. I am an electrician by trade, so very familiar with elctronics, etc. I have the diagram for my model. Without going into a ton of details at this point, here's where I currently stand:

1) Fully charged (and even replaced) the battery. I have 13v at the input terminal on the starter solenoid. Press the gas pedal, solenoid contacts close, but I only get 3.5v on the output side of the solenoid. I do the old "jump the solenoid contacts" with a large screw driver and put my meter Pos + on the starter/generator contact (coming from the solenoid). I still only get 3.5 volts output (weird?). If I disconnect the output side of the solenoid and engage the pedal to close the contacts, it will read the full 13v at the output side of the starter solenoid.

2) To bypass everything on the cart, I hook direct to the battery terminals a set of jumper cables. Then connected directly to the Pos and Neg of the starter/generator and still, the power reading at the starter/generator is only reading 3.5 volts adn the starter/generator does not spin. That eliminates all cart related wiring.

My amateur conclusion: the Stator/Generator is internally shorted. But I'm seeing a lot of threads on here where folks go to change that first and it ends up being something else. I don't really know the internal workings of the S/G, but really hate to throw $130 at a new part just to not fix it.

I'm looking for you veteran Yamaha G-series cart owners for some opinions.

Thanks Guys. Oh, and I'll post some details & pics of mine when I get time to do so (set up for a hunting rig).

[Mr. Mike]

Have you looked at the brushes in the starter generator? They're cheap and easy to replace. There's a youtube video on how to replace them and there are marks on the brushes to indicate whether they're worn out. Other than that I have nothing. I know somebody on BGW knows what else to look at.

How To Change Brushes On A Golf Cart Starter Generator - YouTube

How To Change Brushes On A Golf Cart Starter Generator - YouTube

[neu-rich]

How Old Is Your Battery... Do You Have A Load Tester For Battery... You May Have A Short In The Battery, When You Put A Load On it You Lose Volts...

[raenglehart]

No sir, I haven't pulled the S/G out yet. Guess my You Tube search words weren't very good....as I wasn't finding what I wanted last weekend....lol. I'm just waiting on a day that's not over 100 to pull the S/G and have a look. I hate no longer having a Workshop since we had to move!!

Battery I have charged and/or replaced twice. I even took the one out of my truck which is a Red Top (only a few months old).

Oh, forgot to mention. I have tried turning the clutch by hand back and forth (which has been suggested in some of the reading), it didn't start. However, I need to do that with the meter connected and see if my readings change at all. I don't think I had the meter hooked up when I turned it by hand. I'll update everyone as to any changes as a result.

[cgtech]

I'll bet the wire inside the battery terminal is bad/failing, causing a voltage drop when under load. Try replacing the terminal ends at the battery. I have seen this on several old yami's.

[raenglehart]

I wish it were that simple. Guess I should add I have replaced battery cables (Pos and neg) with new. I mentioned using a new set of jumper cables to by-pass those main cables as suspects. No change.

I'm at it right now. so here's the latest:

I have further isolated to what I think is the S/G.
- When I disconnect the Negative (-) Lead off the S/G, I am getting my full 12v-13v to the S/G Pos (+) terminal as required.
- So, again using the jumper cable Neg side
- I went straight from the battery neg (-) to the Neg (-) post on the S/G.
- Now I only get the 3.5v as previously mentioned on the S/G Pos (+).
- Additionally, with no Ground connected to the S/G Negative (-) post, I checked it for power and am getting the full 12v-13v on the Neg (-) Ground terminal.
**That doesn't seem right, but I think I read somewhere on one of these troubleshooting threads that it is normal to have 12v on the Neg (-) S/G terminal when running? Doesn't seem right to me though. The wiring diagram isn't much help to explain this,

With that new bit of info, what are your thoughts? Tonight is my last opportunity to mess with it until next week, so I'm hoping for some quick-turn answers but understand everyone is getting ready for the Holiday weekend, so may not get much until after.

Thanks to those who have responded with ideas thus-far. Other suggestions always trigger ideas i haven't yet thought to try.

[raenglehart]

- Pressing on: I removed the S/G and was able to bench check it connecting a battery directly to the Pos (+) and Neg (-). It spins up just fine. However, this does not take into account being under a load nor the Voltage Regulator leads. But, my previous readings did not change with the Voltage Reg leads connected or disconnected when the S/G was still installed....WTH?!

- After bench checking successful, I re-installed the S/G. It seems to be functioning just fine now. So, think I'm going to leave it at that for tonight. I'm thinking I may just remove the S/G and do a rebuild/refresh on it (brushes, etc). Thanks for the video earlier Mr. Mike.

[davekayse62]

when I get home tomarrow ill put my multimeter on my starter and do some tests on my g9, ill let you know what the voltages are

[raenglehart]

Originally Posted by davekayse62

when I get home tomarrow ill put my multimeter on my starter and do some tests on my g9, ill let you know what the voltages are

Thanks Dave. Right now it is functioning as it should so I left it be. I was getting carried off by the evening rush of Southern mosquito's anyhow....lol

[raenglehart]

Update:

I got back into town today and jumped back on the cart. It started right up. So, I went ahead and fully installed everything (S/G, Air box, secured all wiring, etc. I have ridden it around for an hour over rough terrain and everything seems to be GTG. I have gone ahead and purchased a S/G rebuild kit (and the Kevlar belts why I was at it )