Yamaha 81 g1 voltage regulator ?

[oklahomacowboy21]

I have a question my g1 which was running ok till you started to go up even a slight hill so I decided to check all electrical connections. Finding the ground wire on the voltage regulator missing its screw with the wire just wraped around the terminal I for just some unknown reason decided to just unhook the ground wire and see what the engine did when I realised it started somewhat better. Moveing the cart to a hill in my back yard and stopping half way up the hill I reconnected the ground wire to the voltage regulator then tried to continue up the hill which the cart would not move just kind of lunge forward as if trying to start i then set the brake and removed the ground wire that i had reconnected the cart then proceded up the hill with power to spare will continue to run like a scalded dog as long as that ground wire is off the voltage regulator. Preformed checks on starter/gen and voltage regulator all seems to be ok batt is chargeing up to 14.3 volts. Called all golf cart mech in my area no one seems to have ever heard of this problem any help much appreciated.

[bigstik40]

Not sure what the actual problem might be, but will offer an explanation as to what is happening. When you unground the voltage regulator, your starter/generator now becomes a starter only and will not be putting any current into your battery. This effectively removes some load from your cart's engine, allowing more power to the wheels. There is a chance that your battery may be bad or have a shorted cell, causing your generator to send maximum charging current into the battery to keep the voltage at 14.3 which is about right. You can check this by measuring the battery open circuit voltage in the morning, after sitting all night. Also, you should check specific gravity to make sure all cells are the same. You should expect the battery voltage to be around 12.5-12.7 volts, if it's good. Also, a good battery should only need a couple of amps from the generator to hold the battery at 14.3 V. Good luck and let us know what you find.-RAY

[oklahomacowboy21]

Thanks Ray I took your advice and pulled batt out of the cart and took it to the parts store this morning had them check it batt checked good so still scratching my head.

[bigstik40]

Did you charge your battery? I would be interested to see what the open circuit voltage of your battery is to determine its state of charge. Even though the battery tests good, it might be in need of a charge. Fully charged the open circuit voltage should be around 12.7 V. Please check voltage and let me know what it is. I'm still leaning toward the generator loading down your engine for some reason. At some point, checking the charging current into your battery while running may be in order. This would require an ammeter or a shunt. If charging current checks out ok, I'll be scratching my head also!!! Let me know the open circuit voltage. - RAY

[bigstik40]

I've been thinking more about your problem and have another idea as to a possible cause. I suppose if your starter/gen. had bad bearings/bushings, the armature could "drag" when generating current, putting a drag on the engine. I know this happens in automotive generators and is also a possibility for golf cars. I've seen your problem posted only a couple times on the internet, with no conclusive fix or reason for the problem. Someone actually put a switch in the system for hill climbing. Just another thought !! Any other help out there appreciated!! We'll keep on truckin - good luck - RAY

[oklahomacowboy21]

Thanks again Ray batt open circuit was in fact low 12.1 volts I charged it all night last night only to find out this morning my charger that I charge my bass boat batteries was not working right. got new charger going to put it on the cart batt when i get home from work will let you know what i come up with when i get a full charge on the battery. I really appretiate all your help and input with my problem. lol i thought about putting in a switch myself for when more horse power was needed may still do it might buy a starter/generator off ebay there only 150 bucks but was tryin to avoid throwin money at it till i got a better idea of whats wrong. Thanks again

[bigstik40]

12.1 v indicates your battery is around 50 % or less of full charge, so your generator will be delivering fairly high current into it for quite some time after starting. This could be your problem. Normally, when the battery is close to fully charged, very little charging current is required to bring it back to near full charge after starting the cart. We'll see how it goes after charging the battery. Let me know. = RAY

[oklahomacowboy21]

Battery is on charger now will try running it in the morning I will let you know how it goes. Thanks you may have solved my problem fingers are crossed.

[oklahomacowboy21]

Batt fully charged no change still doing the same thing. Thought id let you know what I came up with. Thanks

[bigstik40]

OK - That eliminates THAT as the problem !! There is still something wrong, because the generator shouldn't bog your engine down that much. I have pulled the wiring diagram for your cart and am currently looking at it. Quite a complicated wiring there between the two solenoids, starter/gen, and battery !! Have you looked at it yet ?? My next thought is that maybe there is a problem with one of the solenoids, but not sure yet how to test. Let me study the wiring a bit and I'll give you some suggestions for testing. FWIW - At first look, I think it may be possible that an inoperative/defective solenoid could put your generator under a heavy load causing the bog. It would be a current independent of the battery current. If you look at the wiring, you may be able to see what I mean. For example, work out the fwd circuit, then imagine that the rev. solenoid has welded contacts (which would mean that the n.o. contacts are no longer n.o.). Not sure if that's a possibility but that's what I'm looking at. Still looking for any expert opinions here just chime in!!! - RAY