{"product_id":"premium-marine-spark-plug-wire-set-47-88321","title":"Sierra Premium Marine Spark Plug Wire Set – 47-88321 | MerCruiser Thunderbolt","description":"\u003ch2\u003eSierra Premium Marine Spark Plug Wire Set – MerCruiser Thunderbolt Ignition\u003c\/h2\u003e\u003cp\u003eKeep your MerCruiser firing at full strength with this premium spark plug wire set built for Thunderbolt ignition systems. Plug wires degrade over time from heat cycling, vibration, and moisture exposure — when resistance climbs, misfires, rough idle, and power loss follow. This Sierra set replaces worn wires with marine-grade materials engineered to deliver consistent, high-voltage spark in demanding on-water conditions.\u003c\/p\u003e\u003ch3\u003eCompatible Applications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eMerCruiser engines equipped with Thunderbolt ignition systems\u003c\/li\u003e\n\u003cli\u003eRefer to Sierra part number 47-88321 application guide for specific engine models and years\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eKey Features\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eKevlar® core\u003c\/strong\u003e — maximum durability and long service life under continuous vibration\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStainless steel wound conductor\u003c\/strong\u003e — optimized for maximum horsepower and consistent engine performance\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePremium silicone jacketing and boots\u003c\/strong\u003e — high-temperature protection against engine bay heat\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSuperior RFI suppression\u003c\/strong\u003e — shields sensitive onboard electronics from ignition interference\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCorrosion-resistant stainless steel terminals\u003c\/strong\u003e — at both spark plug and distributor ends for maximum conductivity\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOE-style sealed boots\u003c\/strong\u003e — barrier against heat, dirt, and moisture intrusion\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication-specific magnetic suppression core\u003c\/strong\u003e — precision fit for your engine configuration\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e 47-88321\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIgnition Type:\u003c\/strong\u003e Thunderbolt (MerCruiser)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCondition:\u003c\/strong\u003e New\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eComplete Your Ignition Service\u003c\/h3\u003e\u003cp\u003eFor a full tune-up, pair these wires with a matching distributor cap and rotor from our \u003ca href=\"\/collections\/ignition-components\"\u003eIgnition Components\u003c\/a\u003e collection. Need a different fitment? Also consider the \u003ca href=\"\/products\/sierra-premium-marine-spark-plug-wire-set-47-88021-mercruiser-thunderbolt\"\u003eSierra Wire Set – 47-88021\u003c\/a\u003e, \u003ca href=\"\/products\/sierra-premium-marine-spark-plug-wire-set-47-88032-mercruiser-thunderbolt\"\u003e47-88032\u003c\/a\u003e, \u003ca href=\"\/products\/sierra-premium-marine-spark-plug-wire-set-47-88041-mercruiser-thunderbolt\"\u003e47-88041\u003c\/a\u003e, \u003ca href=\"\/products\/sierra-premium-marine-spark-plug-wire-set-47-88071-mercruiser-thunderbolt\"\u003e47-88071\u003c\/a\u003e, \u003ca href=\"\/products\/sierra-premium-marine-spark-plug-wire-set-47-88101-mercruiser-thunderbolt\"\u003e47-88101\u003c\/a\u003e, \u003ca href=\"\/products\/sierra-premium-marine-spark-plug-wire-set-47-88111-mercruiser-thunderbolt\"\u003e47-88111\u003c\/a\u003e, \u003ca href=\"\/products\/sierra-premium-marine-spark-plug-wire-set-47-88201-mercruiser-thunderbolt\"\u003e47-88201\u003c\/a\u003e, \u003ca href=\"\/products\/sierra-premium-marine-spark-plug-wire-set-47-88211-mercruiser-thunderbolt\"\u003e47-88211\u003c\/a\u003e, \u003ca href=\"\/products\/sierra-premium-marine-spark-plug-wire-set-47-88221-mercruiser-thunderbolt\"\u003e47-88221\u003c\/a\u003e, \u003ca href=\"\/products\/sierra-premium-marine-spark-plug-wire-set-47-88281-mercruiser-thunderbolt\"\u003e47-88281\u003c\/a\u003e, or \u003ca href=\"\/products\/sierra-premium-marine-spark-plug-wire-set-47-88291-mercruiser-thunderbolt\"\u003e47-88291\u003c\/a\u003e. Need a single replacement lead? See the \u003ca href=\"\/products\/premium-marine-spark-plug-wire-6-47-88161\"\u003eSierra 6\" Spark Plug Wire – 47-88161\u003c\/a\u003e.\u003c\/p\u003e\u003chr\u003e\u003ch3\u003eParts Desk Insights\u003c\/h3\u003e\u003cp\u003eAt 857g, the 47-88321 sits in the heavier range of this Thunderbolt wire family — consistent with a larger displacement V6 or V8 MerCruiser application with longer wire leads. It’s the right call when a high-output Thunderbolt engine is misfiring under load, idling roughly, or showing intermittent spark after spark plugs have already been inspected and cleared. Replace the full set at once rather than individual wires to maintain consistent resistance across all cylinders. Always confirm your engine model and year against the Sierra 47-88321 application guide before ordering — Thunderbolt wire sets are engine-configuration-specific and not interchangeable across the family.\u003c\/p\u003e","brand":"LNS","offers":[{"title":"Default Title","offer_id":51250811371556,"sku":"47-88321","price":153.79,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/47-88371_cc3b428f-6f7d-4d38-97cd-e8788aac5d31.jpg?v=1786510569","url":"https:\/\/marisolmarine.com\/products\/premium-marine-spark-plug-wire-set-47-88321","provider":"Marisol Marine Company","version":"1.0","type":"link"}