I bought a new deck idler pulley for my Scotts s1742--part #13-10737 but it doesn't have an insert which narrows the center hole diameter. I tried to punch the center out of the old one but it seems to be attached... it's listed as the correct part... and looks identical except the center is missing some sort of insert that narrows the opening and extends out of the center by about 2" to have the pulley slightly raised... any ideas? Thanks.