Second Solenoid on Golf Cart
 

I have a 1992 or 1993(?) Yamaha G-9 Electric golf cart. Everything works fine. It has been fitted with a higher speed motor, does 21 mph and all is well. My question is I see a second solenoid other than the one used for main motor starting etc..
The second solenoid is activated by a switch up front on a panel and it looks like it is stock from Yamaha. I looked at the wire routing on the solenoid and when activated, it jumpers out two
of the posts on the motor. Why would anyone do that ? Does it
basically change the motor to a shunt type motor rather than a serial motor ? I, by all means, am not a expert about golf carts.
Would like to know if anyone knows what and why this solenoid is there...

Thanks, Flip