ElectroMaax Serpentine Pulley Upgrade Kits replace a marine engine's single-groove pulley system with a serpentine (multi-groove) setup, giving a lasting fix for belt dust buildup. They're built to work with ElectroMaax High-Output Marine Alternators from 100 to 250 amps, letting you increase alternator output without added strain on the engine or electrical system. Kits are available for most Yanmar marine engines from the mid-1970s to current models, and for most Nanni marine engines, with a tensioning arm included for JH, GM, QM, and YM Yanmar series engines to make belt tensioning easier. Kits for other popular marine engine brands are available or in development. Upgrading to a serpentine pulley kit can nearly triple alternator amperage while reducing fuel consumption, which extends cruising range and shortens the time it takes to recharge your batteries at anchor. Key Features Permanent solution to serpentine belt dust buildup Compatible with ElectroMaax High-Output Marine Alternators (100–250A) Fits most Yanmar marine engines from the mid-1970s to current models, and most Nanni marine engines Includes a tensioning arm for JH, GM, QM, and YM Yanmar series engines Machined 6061 aluminum construction with corrosion-resistant anodizing 10-rib serpentine belt for smooth operation and better traction Select your engine model above to find the correct kit for your application.