Balmar Serpentine Pulley Kit for Yanmar 2GM20, 3GM30

Description

The Balmar AltMount Serpentine Pulley Conversion Kit is designed for compatible Yanmar 3GM-series diesel engines, including the 3GM30-F and 3GM-F applications. The conversion replaces the conventional accessory-belt arrangement with a J10 ten-groove serpentine system that can transfer more mechanical load to a high-output alternator.

A wider serpentine belt provides greater pulley contact than a traditional single-V belt, helping reduce slip when alternator output and charging demand increase. This can be especially valuable on cruising boats where large house banks require long periods of high-output alternator operation.

The kit includes three ten-groove J10 pulleys, two 40-inch-circumference J10 belts, and mounting hardware. One belt is used in the conversion while the second can be carried as an onboard spare. Supplying the pulleys as a matched set helps maintain consistent groove alignment throughout the accessory drive.

An installation using an AT-200A alternator may require a longer belt than the standard 40-inch belt supplied. For compatible Yanmar 3GM installations moving to higher alternator output, this Balmar kit provides the key pulleys, belts, and hardware needed for the serpentine conversion. Compare with our other alternator mounts & pulleys.