Electrical wires on hydraulic pump

[GomerF]

My old 410 backhoe (supposedly 1972) has a hydraulic pump with two wires (see pic). What is that little attachment to the pump that they come from? One wire goes to ground. The length of the other wire obviously goes to the starter solenoid. Should it be connected to continuous or momentary voltage? If I knew what the little attachment on the pump was for, the answer would probably be obvious, but I don't.

I just had to have a new armature in the starter and the repairman put on a new solenoid. Unfortunately my 81 year old memory is not very great anymore, so when I take things apart I tend to leave the nuts on things where they normally go. If nothing is attached to a lug the nut is tight, and just finger tight for something that gets wires attached. The new solenoid has tightly attached nuts, so I can't be sure of where the wires go. My father always said "Don't get old." This is the reason.

Besides the main lug for the battery cable are two small lugs on the solenoid. One of those lugs gets power momentarily only when you turn the key. The other lug supplies voltage all the time. My question is which of those two lugs should the second wire from the hydraulic pump be attached to?

Thanks muchly for your help, G-

 

[mg2361]

Welcome to HEF Gomer!

That solenoid is the destroke solenoid. Its purpose is to keep the pump from loading down the engine during cranking. It is wired to the starter solenoid "S" terminal. It should only have voltage when cranking.

 

[GomerF]

My thanks mg2361. And so fast. I did think it looked like a solenoid, but why? Appreciate your knowledge.