MerCruiser Alternator Upgrade: Balmar Alternators by Engine Model

This table lists the MerCruiser engines in Balmar's published fitment data that a Balmar high-output alternator we supply will fit. For each engine it shows the original alternator Balmar matched, the belt types it lists, and the Balmar alternators that fit. Balmar's list covers engines introduced up to 2002. For a newer engine, or one that isn't listed, ask us.

How to use the table

1. Find your engine model, and the years if the model appears more than once.
2. Check the belt on your current alternator. A single V-belt, two V-belts side by side (dual V), or a flat ribbed serpentine belt each need a different pulley. Order the Balmar pulley that matches your belt.
3. Choose a Balmar alternator from the table; the list under it links each model code to its product page. Higher amps charge faster but load the engine and belt more. Every Balmar alternator needs an external regulator; our regulator guide compares them. Each Balmar alternator kit includes the pulley and regulator you choose and takes 5% off the full set.

The original alternator numbers are Balmar's parts-catalogue cross-references. They may not match the number on your alternator's label, so check the mount and belt as well.

MerCruiser engines and the Balmar alternators that fit

The Balmar alternators in this table

• 60-100: 60 Series 12V 100A, 3.15in saddle (dual-foot) or the full kit with pulley and regulator, 5% off (pulley options: single V, dual V or 6-rib serpentine (K6))
• 60-120: 60 Series 12V 120A, 3.15in saddle (dual-foot) or the full kit with pulley and regulator, 5% off (pulley options: dual V or 6-rib serpentine (K6))
• 621-100: 621 Series 12V 100A, single-foot or the full kit with pulley and regulator, 5% off (pulley options: single V, dual V or 6-rib serpentine (K6))
• 621-120: 621 Series 12V 120A, single-foot or the full kit with pulley and regulator, 5% off (pulley options: dual V or 6-rib serpentine (K6))
• XT-DF-170: XT Series 12V 170A, 3.15in saddle (dual-foot) or the full kit with pulley and regulator, 5% off (pulley options: dual V or 6-rib serpentine (K6))
• XT-DF-250: XT Series 12V 250A, 3.15in saddle (dual-foot) (pulley options: dual V or 6-rib serpentine (K6))
• XT-SF-170: XT Series 12V 170A, single-foot or the full kit with pulley and regulator, 5% off (pulley options: dual V or 6-rib serpentine (K6))
• XT-SF-250: XT Series 12V 250A, single-foot (pulley options: dual V or 6-rib serpentine (K6))

Belts

We don't sell belts. Balmar's pulleys take standard belts: 1/2 in (13 mm) V-belts, or 6-rib serpentine belts. If the new pulley sits in the same line as the old one and is a similar size, the existing belt may still fit within the adjuster's range. If not, run a string around the belt path to measure, or take the old belt to an auto parts or engine supplier to match the length.

See every Balmar alternator, regulator and pulley on our Balmar page, or ask us to check a fit.