{"product_id":"marine-alternator-12v-70a-self-exciting-ignition-protected-57-20102","title":"Marine Alternator 12V 70A – Self-Exciting, Ignition Protected | SKU 57-20102","description":"\u003cp\u003eA 12-volt, 70-amp self-exciting marine alternator built for gasoline inboard engines where ignition protection is required. This unit features ignition protection screens that prevent internal sparks from igniting fuel vapours — a critical safety requirement for closed engine compartment installations on gasoline-powered vessels. The self-exciting design eliminates the need for an ignition exciter wire to initiate charging, simplifying the installation and removing a common fault point on older engine wiring. An internal voltage regulator, single groove V-belt pulley, and negative ground configuration complete the direct-fit specification.\u003c\/p\u003e\n\n\u003cp\u003eThis is a separate part number from the \u003ca href=\"\/products\/marine-alternator-12v-70a-self-exciting-ignition-protected-57-20104\"\u003e57-20104\u003c\/a\u003e unit in the same self-exciting series — both share identical specifications but are matched to different engine mounting configurations and OEM applications. Confirm your existing part number or engine application before selecting between them.\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 and existing part number — mounting foot dimensions, pulley groove count, 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 57-20102\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\n\u003ca href=\"\/products\/marine-alternator-12v-70a-self-exciting-ignition-protected-57-20104\"\u003eMarine Alternator 12V 70A Self-Exciting Ignition Protected – SKU 57-20104\u003c\/a\u003e — same specs, different OEM application\u003c\/li\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\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eParts Desk Insights\u003c\/h2\u003e\n\u003cp\u003eThis unit and the \u003ca href=\"\/products\/marine-alternator-12v-70a-self-exciting-ignition-protected-57-20104\"\u003e57-20104\u003c\/a\u003e are the most common source of confusion in our alternator catalog — they share the same voltage, output, and feature set, but are matched to different engine OEM applications and may differ in mounting foot geometry or connector type. If you are replacing an existing alternator, the safest approach is to match the part number stamped on the original unit rather than relying solely on specs. If the original part number is missing or illegible, match the mounting foot dimension and pulley groove count physically before ordering. The ignition protection screens and self-exciting design make both units the correct choice for any gasoline inboard application — these are not optional features on an enclosed-compartment gasoline engine. At 70 amps, output capacity is sufficient for a full electronics suite on a mid-size inboard cruiser. Replace the V-belt at the same time as the alternator whenever possible — belt wear accelerates bearing wear on a new unit and is a frequent cause of early failure and undercharging complaints.\u003c\/p\u003e","brand":"LNS","offers":[{"title":"Default Title","offer_id":50992569745444,"sku":"57-20102","price":359.69,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/57-20102_3e2a213e-1cd0-43be-b969-db7f377cfeaa.jpg?v=1782713947","url":"https:\/\/marisolmarine.com\/products\/marine-alternator-12v-70a-self-exciting-ignition-protected-57-20102","provider":"Marisol Marine Company","version":"1.0","type":"link"}