{"product_id":"marine-alternator-12v-70a-self-exciting-ignition-protected-57-20104","title":"Marine Alternator 12V 70A – Self-Exciting, Ignition Protected | SKU 57-20104","description":"\u003cp\u003eA 12-volt, 70-amp self-exciting marine alternator built for gasoline inboard engines where ignition protection is a safety requirement. Unlike standard automotive alternators, this unit features ignition protection screens that prevent internal sparks from igniting fuel vapours — a critical safety specification for closed-engine-compartment installations on gasoline-powered vessels. The self-exciting design means it does not require an ignition exciter wire to begin charging, simplifying installation and eliminating a common fault point on older wiring. An internal voltage regulator, single groove V-belt pulley, and negative ground configuration round out the direct-fit specification.\u003c\/p\u003e\n\n\u003ch2\u003eCompatible Applications\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eGasoline inboard marine engines requiring a 12V ignition-protected alternator\u003c\/li\u003e\n  \u003cli\u003ePCM (Pleasurecraft Marine) inboard engines with single groove V-belt drive\u003c\/li\u003e\n  \u003cli\u003eCrusader Marine inboard engines with single groove V-belt drive\u003c\/li\u003e\n  \u003cli\u003eIndmar Marine inboard engines with single groove V-belt configuration\u003c\/li\u003e\n  \u003cli\u003eOther OEM gasoline inboard applications specifying a 70A ignition-protected, self-exciting alternator\u003c\/li\u003e\n  \u003cli\u003eVerify fitment against your engine serial number — pulley groove count, mounting dimensions, and wiring connector must match before ordering\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSKU:\u003c\/strong\u003e 57-20104\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eVoltage:\u003c\/strong\u003e 12V\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOutput:\u003c\/strong\u003e 70 Amps\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eStarting:\u003c\/strong\u003e Self-exciting (no exciter wire required)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSafety:\u003c\/strong\u003e Ignition-protected — screens prevent internal sparks from igniting fuel vapours\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRegulator:\u003c\/strong\u003e Internal voltage regulator\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGround:\u003c\/strong\u003e Negative ground\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePulley:\u003c\/strong\u003e Single groove V-belt pulley\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eType:\u003c\/strong\u003e Aftermarket direct replacement\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCondition:\u003c\/strong\u003e New\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eRelated Products\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/marine-alternator-12v-55a-replaces-mercruiser-817119a1\"\u003eMarine Alternator 12V 55A – Replaces MerCruiser 817119A1 (57-60050)\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/marine-alternator-12v-65a-replaces-mercruiser-805447t\"\u003eMarine Alternator 12V 65A – Replaces MerCruiser 805447T (57-60065)\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/marine-alternator-12v-75a-replaces-volvo-penta-3862665-3884950\"\u003eMarine Alternator 12V 75A – Replaces Volvo Penta 3862665 \/ 3884950 (57-60073)\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/sierra-v-belt-47-15455-marine-inboard-sterndrive\"\u003eSierra V-Belt 47-15455 – Marine Inboard Sterndrive\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eParts Desk Insights\u003c\/h2\u003e\n\u003cp\u003eThe self-exciting feature is the key differentiator on this unit and the main reason customers select it over a standard replacement. On older inboard installations where the exciter wire circuit has failed, corroded, or was never wired correctly, a self-exciting alternator eliminates the fault entirely — it begins charging as soon as the engine RPM rises, with no dependency on the ignition circuit. This makes it a reliable upgrade as well as a direct replacement. The ignition-protection screens are not optional on gasoline inboard engines — they are required to meet ABYC E-11 and UL 1428 safety standards for enclosed engine compartments. If you are replacing an alternator on a gasoline inboard and the replacement unit is not ignition-protected, it should not be fitted. At 70 amps, this unit comfortably handles a full complement of navigation electronics, bilge pumps, and lighting on a mid-size inboard vessel. When replacing, inspect the V-belt and tensioner at the same time — a stretched or cracked belt under a new alternator is a common cause of undercharging and noise at idle.\u003c\/p\u003e","brand":"LNS","offers":[{"title":"Default Title","offer_id":50992569843748,"sku":"57-20104","price":357.09,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/57-20104_939a840f-5775-4e26-b059-e4eb550aa547.jpg?v=1782713949","url":"https:\/\/marisolmarine.com\/products\/marine-alternator-12v-70a-self-exciting-ignition-protected-57-20104","provider":"Marisol Marine Company","version":"1.0","type":"link"}