Generator water pump pulley

[BonesD]

Howdy, I have a Jabsco 2620-1101 raw water pump on my generator that has twice thrown the drive pulley. Set/grub screw has been tightened and used blue loctite.
The set screw threads down on top of the key stock.
I have looked a part list for this pump and I don’t see that it has or should have a washer and bolt screwing in the end of the pump shaft to prevent the pulley from walking off the shaft.

Can anyone tell me if there should be hardware on there to prevent this from occurring?

With out removing the pump I can only tell that there is a hole in the end of the shaft and that it’s about .112 in diameter. I can’t see it well enough to determine if it’s threaded or not.
Is Jabsco hardware US or metric?
Thank you

 

[Lepke]

Pump shaft hole is a center hole for machining processes, no threads. If the pump pulley isn't parallel with the crank the pulley will walk if the set screw is loose. Put a straight edge across the 2 pulleys.

 

[BonesD]

You are right in both cases. The pump sits at a poor angle to the main drive pulley causing the walk. I pulled the pump and bracket and could see it was just a centering hole for machining the shaft. I imagine it could be drilled a bit deeper and threaded.
The mounting bracket for the pump is (was) 90 degrees to the block. I put a bit of a tweak in it to try and offset the angle but not enough the first try. I only changed it by about 3 degrees.
Problem is the pump shaft and pulley stick out so far from the mounting holes that it takes very little belt tension to pull the pump over and create the angle.
I’m not sure what the answer is at this point. I’ve got a fresh roll of bailing wire. Maybe that will fix it.
Thanks for your answer.

 

[jleonard]

Can you drill/tap the pulley on the opposite side of the set screw and add another? If so you could put a drill spot on the shaft for the set screw to go into. Or grind a small flat.

 

[Lepke]

I guess the pump is mounted on wood or fiberglass with lag bolts? And the holes are getting big? You could epoxy in an all thread coupling, then you use bolts to hold down the pump.
If the shaft tilts toward the crank, the pulley will walk off the shaft. It it tilts away from the crank, it will walk toward the pump.
One option would be to drill thru the pulley, key and shaft. Buy a taper pin and reamer to match. Drive in the pin, cut excess, and everything is locked together. Possibly a roll pin would hold.
You can buy a taper pin and reamer on Amazon or ebay. Some come as kits, pin with proper reamer.

 

[BonesD]

Good suggestions. Thanks
The pump is hard mounted to the gen engine case. The holes are all good. Just that the mounting holes are a couple inches away from the back of the pulley giving the belt a lot of leverage to pull the pump towards the crank pulley. I don’t see how it would ever have been straight to be honest. I will pull it off again and do some of the above mods. Hard on the pump bearings and the belt the way it’s set up now. I need to change the mount in angle of the pump to make it right

 

[Lepke]

You might be able to shim the pump base. Or maybe elongate the holes in the base and shim the holes to move the base in the direction needed.