Looking for part number or source. Mechanic at marina told me to buy the matched pair if not one will always be loose
Don't have the part number. Usually if you clean the belts, at least one of them will still have a legible number on it.
.Napa or a bearing supply house such as Motion Industries or Bearing Headquarters are good places to go.
The matched sets are sort of a misnomer now. In the old days, there was significant variation in belt lengths with different batches. Current manufacturing methods and standards has minimized the matched set advantage.
Today if you go to a counter and order a matched set, you will often pay extra and the counter guy just goes in the back and compares the belts you get and says good enough to himself then comes out front. Here you go.