MURRAY 30/12HP (31621x66B DoM 3143)

[Fish]

Here is the pulley.

 

[bertsmobile1]

Top pulleys regularly have to be removed with a press which requires removing the entire housing .
Usually the housing breaks when you undo the mounting bolts so you are up for a whole new unit.
Shaft comes out to the blade end so if you can't get the pulley off you cant get the shaft out.

 

[Mike_Torello]

I would say that the coarse spiral was from rotational metal/metal contact. The top piece is just the center of the pulley, It is a snug fit + a woodruff key.

circled red endcap (pulley center) is just snug fit? should be heated a little and light tap to release?
circled greenis spaces that is also rusted snug fit i guess :S
circled blue is coarse threading I had in mind... that can't be from metal to metal contact, it hast to be machined so I'm guessing they lathe fitted some rod to spindle, even made lug nut thread different than original...
circled pink is woodroff key that is actually made by welding material to the shaft, it's not removable and it's not notched in spindle, so I don't know what to expect under that end cap remains of pulley center...
by the looking of blade it has "5 leaf clover" hole like Husquarna has, so I'm guessing that spindle assembly is some sort of Frankenstein, because lack of Murray parts in this part of EU :S

Top pulleys regularly have to be removed with a press which requires removing the entire housing. Usually the housing breaks when you undo the mounting bolts so you are up for a whole new unit.

you can't remove this one with press because it's blind cap on top of spindle :S that's why we cut already rusted-welded-rusted-welded pulley to try remove it (BTW. I tougth I will have more trouble finding spare housing than pulley... boy I was wrong...), and housing was already broken when we got her, but my father finished it off with using mower with almost no brakes and went over the large stone, so housing was needed either way...

Shaft comes out to the blade end so if you can't get the pulley off you cant get the shaft out.

this shaft came out on pulley side, but if that endcap remains of pulley was removable, I think it can go either way... it's 17mm straight with no wider parts like original bought...

so, verdict... we are dressing up old spindle (returning new bought) and keeping bearing housing but changing bearings to the right inner hole dimension... and then have to find some pulley that is same outer diameter and fit it with lathe on old spindle :S looks a lot of work but wit access to machining and welding tools might be cheaper than ordering again because this wrong purchase costed me $70 already... :S and whole lawnmower was $230... If I go for new spindle, I need to buy all new whole vertical assembly from bottom bolt nut to the top bolt nut, with all accessories :O and that might total with shipping more that whole lawnmower was paid...