Hi lovemygreen,
also, I think you've done well!
The little issues with the machine that Deejay has gone over are fairly common and easy to fix. I've just purchased sprockets and chains for my SB45 resto and the OutdoorKing store is competitively priced. You shouldn't have any problems keeping the parts costs to under $150 and once they're replaced and adjusted correctly, they'll give many years of service if maintained. If you're planning on getting the reel and bedknife sharpened soon, I'd wait until then to change your sprockets and chain, as they have to come off anyway. The clutch thrust pad is cheap and easy to change so you may as well do it asap.
Michael
