Melex Cart jerks and is full throttle

[Bsienki40]

I have a Melex cart I just put in six Deka new batteries it is fully charged. The problem I am having is when I put it in forward or reverse and just barely tap the pedal it jerks and is full acceleration. Also It will only go for about a half mile or so and seems like the batteries are dead. BUT THEY ARE NOT! If I let it sit for awhile it will repeat the above.

[Epb]

You can try researching in the group for melex, harley, etc. It reads like you have an 252 and that wiper arm is quick to the top for full speed, which is how you need to run the resistor cart. The death down the road may be poor contacts or the solenoid is dropping out.

[Bsienki40]

OK I have done a lot of investigating my situation on this and still not SURE what the problem is. I have a Melex 512 E serial number215221 not sure of the year? I am experiencing two problems. First I want to say that I had six new Deka 6 volt bolt batteries with new battery cables installed two day ago. I am getting 38.47 volts total of all the battery pack. Each battery is reading 6.43 volts. The problems are: (1) When I put in forward or reverse and just tap the pedal ever so slowly it will take off full speed there is no smoothness to the accelaeration. (2) The cart will go good speed for about 2 maybe 3 blocks and then it will slow to a crawl and eventually stop.

If I let it sit for awhile ...maybe 5 minutes it will repeat the same thing over nad over and over again. The batteries are fully charged. all connections are cleaned at the motor and silinoid and everywhere. and they are tight!!!!!

It has a Curtis controller not sure if its a 1204 or a 1205. also from the foot pedal linkage it is connected to a pot box. two wires go to the Curtis controller a blue wire and a black wire. I disconnected the blue and black wire at the controller and set my meter to ohms and it is reading.....05 up and speratical reading while pushing it down but stays somewhere more consistanly around 8.32 but will jump up and down.

I understand that it either is 0 to 5k or 5 to 0. so my thinking is it is the pot box that's bad. on the cart dying out is there a pre charge resister in the Curtis controller that would cause that or is it somewhere else or woujld this even cause this to happen?

any help would be awesome!!!

look on the tag on the motor revealing a number combo like 08/78 (August 1978 )

[scooterman]

Sounds like the POT issue is one problem, it should be closer to 5k at full throttle according to your test. The other issue sounds like it is going into limp mode, most likely caused by the speed sensor, located at the end of your motor, a group of small wires. That said, I never heard of one of these carts, nor have a schematic but there are similarities as to how these carts are designed to function.

[scooterman]

http://www.vintagegolfcartparts.com/...=100017&Page=1

is this it?

[Epb]

The pot is 0-5 the manual i have says loose or broken connections in power circuit, brake drag and/or damaged motor. You can buy a manual where scooterman shows. I have not had this problem and it peaks at 12mph.....but you can upgrade

[Epb]

1992

[Jocko09]

I know this is an old post, but I am experiencing the same symptoms. Did you ever figure out what was causing the problem?

[cgtech]

Look up PB-6 testing and adjustment. Totally not a "motor speed sensor" issue, since these melex never had one of those sensors on the "back of the motor" as suggested above (melex were all "series" cars).