AC Delco 41-110 Iridium Spark Plug | GM LS Marine Engines | Pre-Gapped 0.040 in. | Fine-Wire Iridium Tip | Suppressor Seal | OEM Replacement | Sold Individually

AC Delco 41-110 Iridium Spark Plug — GM LS Marine Engines | Pre-Gapped 0.040 in. (1.02 mm) | Fine-Wire Iridium Tip | Suppressor Seal for Marine Electronics | OEM Replacement | Sold Individually

AC Delco 41-110 is an iridium spark plug used as original equipment by GM and marine engine manufacturers in GM LS-series engines. Pre-gapped at 0.040 in. (1.02 mm). Fine-wire iridium tip requires less voltage to fire and provides stable ignition across the RPM range. Suppressor seal reduces radio frequency interference (RFI) with onboard marine electronics. Sold individually — order the quantity needed for your engine.

Part Specifications

• Part Number: AC Delco 41-110
• SKU: ACD-41-110
• Plug Type: Iridium
• Electrode: Fine-wire iridium tip
• Pre-Gapped: Yes — 0.040 in. (1.02 mm)
• Suppressor Seal: Yes — reduces RFI with marine electronics
• OEM Status: Original equipment for GM LS marine engines and a variety of marine engine manufacturers
• Sold As: Individually (single plug) — order quantity to match your engine’s cylinder count
• Primary Application: GM LS-series marine engines

GM LS Marine Engine Applications

The 41-110 is the OEM iridium spark plug for GM LS-series engines used in marine applications. The LS engine family is used by several marine engine manufacturers in stern drive and inboard configurations:

• MerCruiser 4.5L MPI (Gen V): LS-based 4.5L V8 used in MerCruiser stern drives
• MerCruiser 6.2L MPI (Gen V): LS-based 6.2L V8 used in MerCruiser stern drives and inboard applications
• Volvo Penta V8-300, V8-350, V8-380 (LS-based): GM LS-family engines used in Volvo Penta stern drive and DPS drive applications
• Indmar, PCM, and other LS-based inboard engines: The 41-110 is used in LS-based inboard engines by Indmar and PCM used in wakeboard and ski boats
• Verify before ordering: Confirm the 41-110 is the correct plug for your specific engine model, year, and horsepower rating. Some LS marine engine variants may use a different plug number. Check your engine service manual or existing plug for the correct part number before ordering.

Iridium vs Copper — Why Iridium for Marine LS Engines

• Fine-wire iridium tip: Iridium’s hardness allows the electrode tip to be manufactured at a smaller diameter than copper. The smaller tip concentrates the spark at a finer point, requiring less voltage to fire and producing a more consistent spark kernel in the combustion chamber.
• Stable ignition across the RPM range: The lower voltage requirement and consistent spark characteristics of the iridium tip contribute to stable combustion across idle, cruise, and wide-open-throttle RPM ranges on LS marine engines.
• Longevity: Iridium’s hardness and corrosion resistance result in slower electrode wear compared to copper plugs. The 41-110 is rated for extended service intervals as an OEM plug in LS marine engines — follow the service interval specified in your engine manual rather than substituting copper-plug intervals.
• Marine environment: Marine engines operate in a high-humidity, salt-air environment that accelerates corrosion on ignition components. The iridium electrode and OEM plug construction provide better corrosion resistance than standard copper plugs in this environment.
• Carbon deposits: The fine-wire tip geometry and consistent spark combustion reduce carbon fouling on the electrode tip compared to larger-gap copper plugs under the same operating conditions.

Suppressor Seal — Marine Electronics Compatibility

• The 41-110 incorporates a suppressor seal that reduces radio frequency interference (RFI) generated by the ignition system during spark firing.
• Why this matters on a boat: Marine vessels operate with a range of sensitive electronics — VHF radio, GPS chartplotters, depth sounders, and engine management systems — in close proximity to the ignition system. RFI from unsuppressed spark plugs can cause noise, interference, and erratic readings on these systems. The suppressor seal in the 41-110 reduces this interference as part of the OEM ignition specification for LS marine engines.
• Do not substitute non-suppressor plugs in marine applications where the OEM specification calls for a suppressor-type plug.

Application Notes

• Sold individually — order the quantity matching your engine’s cylinder count: 4 plugs for a 4-cylinder, 8 plugs for a V8 LS engine
• Pre-gapped at 0.040 in. (1.02 mm) — verify against your engine service manual before installation; some LS marine engine variants may specify a different gap
• Handle iridium plugs carefully during installation — the fine-wire iridium tip is hard but can be damaged by contact with a hard surface or improper gapping tools; do not re-gap with standard gapping tools
• Thread the plug in by hand for the first several turns to avoid cross-threading; torque to specification per your engine service manual (typically 11–15 ft-lb on LS aluminum heads — verify for your engine)
• Apply anti-seize to plug threads only if specified by your engine manufacturer — many OEM iridium plug installations do not require anti-seize and over-application can cause torque errors
• Change at the interval specified in your LS marine engine service manual; do not extend iridium service intervals beyond the manufacturer’s recommendation in a marine environment

Additional Information

• Vendor: AC Delco
• SKU: ACD-41-110
• Part Number: 41-110
• Product Type: Boat & Engine Maintenance / Spark Plugs
• Plug Type: Iridium
• Gap: 0.040 in. (1.02 mm) pre-gapped
• Sold As: Individually (single plug)
• Country of Origin: USA
• HS Code: 8511.10 (spark plugs — verify for your import classification)

Frequently Asked Questions

Q: What is the gap on the AC Delco 41-110?
A: The 41-110 comes pre-gapped at 0.040 in. (1.02 mm). Verify against your engine service manual before installation — some LS marine engine variants may specify a slightly different gap. Do not re-gap iridium plugs with standard gapping tools, as the fine-wire tip can be damaged.

Q: How many plugs come in this listing?
A: This listing is for one (1) individual spark plug. Order the quantity to match your engine’s cylinder count — 4 plugs for a 4-cylinder engine, 8 plugs for a V8 LS marine engine.

Q: Is the 41-110 correct for my MerCruiser 6.2L Gen V stern drive?
A: The 41-110 is the OEM iridium plug for GM LS-based marine engines including the MerCruiser 6.2L Gen V. Verify by checking the plug part number in your MerCruiser service manual or on the existing plug before ordering, as some engine variants or horsepower ratings may specify a different part number.

Q: Can I use the 41-110 in my Volvo Penta V8-350 or V8-380?
A: Volvo Penta V8 engines in the 300–380 hp range use GM LS-based blocks and may use the 41-110 as the OEM plug. Confirm the correct plug part number in your Volvo Penta engine service documentation before ordering.

Q: Should I use anti-seize on the plug threads?
A: Follow your engine manufacturer’s specification. Many OEM iridium plug installations in LS marine engines do not call for anti-seize — applying it when not specified can cause torque over-tightening errors on aluminum heads. Torque to the specification in your engine service manual (typically 11–15 ft-lb for LS aluminum heads — verify).