Going to negative ground on 620

[RMOMN]

When installing a alt. and going to neg. ground. Will all the gauges still work?
 

[rickdeere]

youll need to change wires around on amp gauge
 

[rickdeere]

youll need to change wires around on amp gauge and coil wires
 

[RMOMN]

Will I need to do anything on the fuel gauge?
 

[buickanddeere]

Nothing to gain by cob jobbing an alternator onto a 620. The factory 20amp generator is a good producer.
An alternator on a two cylinder also looks butt ugly.
Coil polarity is important too.
 

[fixerupper]

I agree with Buick all the way unless you plan on pulling an implememt that requires a lot of juice. The only time I saw a 620 changed to an alternator that really needed one was when the farmer bought a new White planter that had an electric drive of some sort, that he planned to pull with his 620. Jim
 

[RMOMN]

I just bought the tractor to use and that was already done.
 

[fixerupper]

OK, so now you have to work with the hand you're dealt. Like what was said, the ammeter wiring needs to be reversed, the primary wire on the coil changed so the negative side goes to the points. I've had good luck with generators on two bangers. The down side to a genny is the damage to your pocketbook when it comes time for replacement of the genny or regulator. Jim
 

[rickdeere]

no I dont think so
 

[Mike M]

If you have a working fuel gauge now on 12V + grd. It will now not work ! You will have to try and find a neg. grd. gauge.
 

[RMOMN]

Thanks Mike, what gauges will have to be changed now that it is neg. ground?
 

[RMOMN]

Thanks Jim, I'm sure that's why it has a alt. on it. Now I have to figure out what needs to be done so I have working gauges. Bob
 

[Mike M]

Just swap the leads on the ampmeter. The fuel gauge is the only fussy one. Did it work before ? It might not of ? If not it could also have a bad tank sender. But the fuel gauges are definatly ground specific. There are some guys around rebuilding gauges maybe they can make them both + or - grd.
 

[fixerupper]

The only electric gauges are the fuel gauge and the ammeter. I'd be surprised if you DO have a working fuel gauge. Usually the sender gives up the ghost in those old girls. To check it out pull the top dash panel back a bit to get access to the back of the fuel gauge. It's held on by those four 5/16" cap screws that might or might or might not twist off. Find the wire that comes off the top of the fuel tank to the fuel gauge and ground the terminal it hooks to with the switch turned on. Just bump the grounding wire to the terminal in case you're touching the hot one. You should NOT have sparks at all. If you are getting power to the gauge and the gauge itself works and you are touching the right terminal it should peg full. If there's no reaction, run a jumper wire from a hot source to the power side of the gauge and try it again. When you first touch the jumper wire to the gauge just bump it to the gauge to see what happens in case there's a short somewhere that makes smoke. You'll figure it out. It's pretty straight forward. If the sender is bad they are available now in the reproduction market but I'll be darned if I remember where. Someone else might chime in. I got a repro sender and refurbished gauge for my 630 and it works fine. Jim
 

[gtx1967jewison]

20 amps wont even run a decent, practical set of healights. They draw 30. If gennys are so great why were they $hit canned for 'new-fangled' alternators? Because more power & LESS maintenance were desired. My opinion is they only belong on trailer-queens/parade toys. To each his own.