some background
new to me 2001 E4 has about 6000 miles
new 1 week old Deka Gels, Vivan charger just upgraded with selector switch, timer, & micro upgrade. original 3.5HP as far as I can tell.
I’m questioning the tire size the previous owner went with
165/60/14 is probably too much tire for an old 3.5HP?
with the new batteries finally in and charged, four of us went out on a 3 mile run, not steep terrain, but flat to mild inclines, it was about 60 degrees outside. We started smelling something melt, but the cart ran fine and fast the whole time. I hit 32 on the speedo and confirmed it with a hand held GPS the next day. the motor got very hot, over an hour later it was till hot to the touch. Do I need to get back to 12" tires, or should I upgrade the motor and leave the 14" tires on?
Any feedback is appreciated, I’m not primarily looking to make it fast, I’m more interested in less maintance & longer battery life
Was the motor any trouble before the other work was done? In normal use the motors have been reliable for our four GEMs over the last nine years. Only bearings, o-rings, sensors, and brushes have been changed in about 30,000 combined miles.
Most likely, your motor is overloading because of running tires that are too large. The factory can tell you which motor you have by looking up the serial number. I have been told that all pre-2005 72 volt motors, both 3.5 and 5 HP will interchange. Since I haven’t worked on any GEMs older than 2002, you may want to check for yourself. There are, of course, loads of after market controllers and motors that will boost power and speed. Then heavier cables and more powerful batteries may be in order.
Less likely is that the motor is either worn out and may need the armature cleaned up and brushes replaced. Arrowhead Electric in California has sold us these in the past. Also, oil may have entered the motor through the trans axle input shaft. If this is the case, a new bearing and o-ring will stop the leak. These are not sold by GEM, but you find them elsewhere. All of the oil will then need to be carefully removed from the insides of the motor and thoroughly dried out before reassembly. If you got any other questions, please ask.
Daniel
[QUOTE=GEMmechanic;9127]Was the motor any trouble before the other work was done? In normal use the motors have been reliable for our four GEMs over the last nine years. Only bearings, o-rings, sensors, and brushes have been changed in about 30,000 combined miles.
Most likely, your motor is overloading because of running tires that are too large. The factory can tell you which motor you have by looking up the serial number. I have been told that all pre-2005 72 volt motors, both 3.5 and 5 HP will interchange. Since I haven’t worked on any GEMs older than 2002, you may want to check for yourself. There are, of course, loads of after market controllers and motors that will boost power and speed. Then heavier cables and more powerful batteries may be in order.
Less likely is that the motor is either worn out and may need the armature cleaned up and brushes replaced. Arrowhead Electric in California has sold us these in the past. Also, oil may have entered the motor through the trans axle input shaft. If this is the case, a new bearing and o-ring will stop the leak. These are not sold by GEM, but you find them elsewhere. All of the oil will then need to be carefully removed from the insides of the motor and thoroughly dried out before reassembly. If you got any other questions, please ask.
Daniel[/QUOTE]
I pulled the motor and the differential case is black with smoke residue, the motor is a tough guy however it still runs and bench tests well. The problem is that the previous owner had the controler modifeid to go up to 32 MPH and put on a 165/60/14 tire & wheel pkg this with the old 6000+ mile original 3.5 HP. So I decided to buy the 7.5 R4F motor and will get the controler to match the system without overloading anything. this 2001 has the older 8.9:1 ratio. I’m more interested in a balanced long lasting, low mainyanance car. Not to concerned with top end speed.
The input bearing was pulled and it looks, sounds, rotates perfect so I’m sticking with it. I reinstalled the O ring with a slight bead of permatex silicon in the case, then again a slight bead around the bearing before the snap ring was attached. This wasn’t my idea but was suggested by a tranny shop guy who looked over the bearing and said it was like new. I’m not worried about leaking, but down the line if I see a drop of gear oil I’ll replace the bearing and O ring. Thanks for the Mcmaster-carr info on that as well.
Bill