[egad]

Capacitor is installed with the correct polarity. I removed everything from the two big terminals, and one small. Measured between the to large terminals and there is no connection. I guess it should read 0 Ohm?
When i first started it it took me a while to shut the cart down, and smoke came from the cart. Also the ground connection melted. Maybe the solenoid now is broken.

I also found What probably caused the problem. There is a small black cable going from the solenoid to the controller. I had it connected to B+ on the controller. Today i discovered that i should be connected to B-. I changed this, but the cart still goes full speed when i connect the +cable to battery. Even though the -cable is not connected to battery.