Take it all apart, lube/oil all to be sure everything moves smoothly.. A tad of grease inside the plunger (you’ll need to cut the pull-tie to get is apart) and a tad on the lever where it is being pushed..
Also, cut the black wire & wire to the mount directly as shown–much better ground than going over to the other side of the block.. Way less voltage drop, especially when starting.
Be sure the solenoid mounts BELOW the bracket, not on top.
Learning how the system works is the key–Your engine is “energize to run”, so when the key if off, the solenoid is EXTENDED as it´s internal spring is defeating the “natural” always-run position of the ND pump.
|BLACK||Goes to ground|
|RED||Run position — draws about 1-2 amps when energized and I call it the “hold position”|
|WHITE||Starting position wire and is only energized when cranking the engine thru the magnetic switch that also operates the Bendix on the starter — draws about 50 AMPS and I call it the “suck in” circuit.|