Kenmac,
I few months ago there was a lead to a person who said he had the part. I contacted him and he had a type "A". My mower has no "A" or "B" designation. I purchased the part from him to try. It did not fit.
This center pulley has a tapered shaft. Other models seem to have a straight shaft.
I was thinking about maybe trying a JD double sheave......but not sure where to start. The old JD 400 mowers had a double sheave pulley on the front.....but I am not sure if it was tapered.
On another thought. Do you know the what model a YM155D crosses over to on the JD line?