Does this look like your control spool? This one is style on my 150.
IT manual stated to insert a pin punch into one of the hose ports to hold spool and unscrew linkage end. WRONG. I had to remove the seal (small chisel) and then there is a spiral snap ring behind the seal to hold the spring and spool. I had to use dental picks to remove the little bugger. The seal number is SKF 6741. On the other end is a dust cover, mine had drive rivets to hold cover. Just pry it off, it doesn't seal anything. There is an internal O-ring in the housing that the spool end seals within.
Hope this helps