"IF I loosen the nut that holds the blade on, the pulley will turn OK. But ,when I tighten the blade, the pulley again freezes. Any ideas?"
"could the grease fitting be too long; thereby rubbing pulley shaft?"

Hardly thinks so, no logic there anyway, loose blade nut and it turns OK? Grease zerk too long?

I'd say you are missing a spacer washer between the blade and the blade drive collar letting the blade drag on the lip of the hub - regardless, it is obviously a spacer problem, did you have the shaft out?

Walt Conner

Did not have the shaft out. Simply took old blades off and put new ones on. There were no spacer washers thaat I saw, BUT after reading your post, I checked and it does appear tha blade is rubbing the housing. What kind of washer would it take, and should the other blade have the same size? The other blade turns ok and appears to have a small amount of clearence - maybe 1/32 or so. Could this cause unlevel mowing? THANKS

1/32 seems pretty tight to me.

Are the blades on upside down? If not, are the blades generic replacements or designed for that mower?

I suspect there was a thin washer that stuck to the old blade when you took it off and you didn't notice it. You will never notice any height difference that small.

Go to local farm supply or good hardware and get a washer. Thickness of blade is not going to affect that situation.

Walt Conner