The Balmar 621 Series 100A Spindle Mount Alternator has a J10 AltMount serpentine pulley and isolated ground, for single-foot mounts.
Spindle mount is the single-foot arrangement, covering 1-inch Motorola-style and 2-inch Delco-style fittings. One inch suits Westerbeke, Lehman, Hino and Pathfinder; two inches covers Volvo Penta, John Deere, Perkins and MerCruiser. The engine decides, and neither will fit a dual-foot saddle bracket.
The J10 ten-rib pulley needs a matching ten-groove belt, against the K6 version for six-groove drives. Counting the ribs on the belt currently fitted is the quickest way to establish which is correct.
Isolated-ground construction keeps the charging return in a dedicated cable rather than through the engine block and bonding. This is the alternator alone, so an external regulator and temperature sensors need specifying alongside it. Explore more marine alternators.
- Single-foot spindle, not a dual-foot saddle
- 1-inch and 2-inch cover different engine groups
- J10 needs ten grooves, K6 needs six
- Count the ribs on the belt already fitted
