Key Features

• High-Torque Performance: Specifically designed to transfer the massive mechanical load of 100A to 170A alternators without stretching or slipping.

• K6 Serpentine Profile: 6-groove design maximizes surface area contact with the crank, water pump, and alternator pulleys.

• Precision Fit: 48-inch (1219mm) circumference, optimized for the geometry of the Yanmar 4JH3 engine block when equipped with Balmar pulleys.

• Synthetic EPDM Construction: Resistant to heat, oil, and engine room contaminants, ensuring a longer service life than standard automotive belts.

• Reduced Noise: The serpentine design runs significantly quieter than traditional single or dual V-belt setups.

Technical Specifications

What’s In The Box?

• 1 x Balmar 48-B-48 Serpentine Belt: A premium, heavy-duty 6-groove (K6) EPDM belt with a 48-inch circumference.

• Product Sleeve/Label: Includes the Balmar part number and barcoding for easy identification and inventory management.

Critical Spare Parts Advice

When purchasing the 48-B-48, many experienced cruisers follow the "One to Use, One to Spare" rule. Because these belts are part of a proprietary AltMount conversion system, they are rarely found at local automotive or general hardware stores.

It is highly recommended to keep a secondary 48-B-48 in your onboard spares kit to prevent being stranded without a charging system or water pump operation.

Related Components (Sold Separately)

If you are performing a full maintenance cycle on your Yanmar 4JH3, you may also need:

• Balmar AltMount Pulley Kit: If you do not already have the serpentine conversion hardware.

• Belt Tensioner Tool: To ensure the 48-inch belt is seated with the correct deflection.

• Replacement Pulley Shims: Useful if you need to re-align the alternator after a belt change to prevent "dusting."

Pro Tip: Always keep a spare 48-B-48 belt on board. High-output alternators put significantly more stress on belts than factory units; having a backup ensures you aren't left without charging power in remote locations.