Symptoms of a Bad Motor?

@oldhouseboater (Rod) will service your motor for a small amount .

Spoke with rod yesterday. He’s 100% it’s the motor. His fee is a no brainer… the shipping stinks from CA to Fl and back.

I have an AC motor and controller arriving this week from @MikeKC and @Inwo. The inquisitive side of me wants to send out the motor to see if that was my problem. The financial side says cut your losses, focus on AC, circle back to DC if I can’t make AC work.

Look at it this way. Your motor at present is valueless. a Rodney Refurbished motor has a value of $450 on Ebay.

once I get a change to pull it out of the car; I’ll send it to you (@Old_Houseboater). I’m sure I’ll end up picking up another GEM to rebuild and it will be good to have a working motor around.


In a message dated 6/11/2020 11:37:26 AM Eastern Standard Time, writes:

Finally got around to breaking down the GEM and pulling the motor. Think I’ve gotten to the root of my problem. Looks like the differential is due for a rebuild (and the motor too).

@Old_Houseboater should have a blue top motor coming your way soon. Any chance you want to sell me some spicer rebuild parts and ship them back with the motor?

Bearings, seals and a shaft kit? what ratio?

In a message dated 6/21/2020 6:12:53 PM Eastern Standard Time, writes:

I would have tryed this trick. Take your car and put it on jacks. Take some electrical cleaner (spray can) and take the vented brush guard off the motor and run some electrical cleaner threw the motor as some one in the car drives it. Most likely the brushes are stuck and that’s the jearking /on & off your talking about.

Rodney how often do they say the Brush Head
Should be removed from the motor and the brushes cleaned

yes to all of those… and whatever you’d recommend while I have it broken apart. I’d want to convert to a 10:1 ratio.

It varies with brand I suggest 3 years for the first service for AMD (black) motors 4 years for D&D (blue) motors and 5 years for GE. Every 5 years there after.

The AMD motor is the most precise motor with the closest tolerances. For this reason it is the first one to have the brushes stick and fail. This has caused them to suffer reputation wise when they are really an outstanding unit. The D&D are a bit looser but will usually start to fail about 4 years in. GE motors are the most forgiving but will eventually quit, When I refurbish a motor I will adjust brush clearance to allow 5 years between service. NOTE: carts stored outside in damp dusty areas and not used regularly can develop corrosion between the brush ends and commutator that will prevent contact , cause arcing, and require machining of the commutator surface.

.What ratio is it now. You really need to rebuild the ratio that exists. Buying a set of gears costs too much

good question…

it’s a 2000 4 seater that came with a 3.5Hp motor. Manual suggests 8.91:1

In prior threads, folks with more GEM knowledge than me have said it’s 9:8:1.

Now that I have it out of the car, I marked the input shaft and the axle shafts. counted rotations and it was 9 in the input to get the axle shaft to do a full loop.

I happen to have 2 spares which are both 8.91:1. I’d rather have a 10x:1 so I have the spread of options to mess with.

8.9 gear boxes are in demand by the hot rod guys . You should be able to work a trade.

Ratios for Classic’s: 8.9, 10.35, 12.44, and 14.76

If you stick with 21" or smaller diameter tires 8.9 works real well. There are some real nice low profile tire sets available . I run 8.9 with 21" tires on my 84 volt 4 seater. Very happy with it. My brake mod works real good with the 21 inch tires and I can lock the rears.

Ok… well, right now… I don’t have a particular need since I put the 12:44 in my car. I’m just positioning for my next build. I just want to learn how to break down one of these gearboxes and put it back together. I’ve never opened one up before.

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I have a 7.5 AMD motor (black) that was sitting a long time and the brushes were stuck, I ended up breaking the one brush holder trying to loosen them, were do I buy parts for this motor?

I repair/refurbish all GEM DC motors

Here’s what I need, The plastic frame that holds the brushes. Thanks

I bet you could send the whole end cap (pictured) into Rodney and he’ll fix it for you. It looks like the casting could also use a good cleaning.

Hey Rodney, To you have a bead blaster?

Post a pic of your rotor (specifically the comm end) so he can judge if that needs to be turned.

I use a sand blaster

I have parts.Email me directly