Spark Plug ACDelco 41-993 Iridium Plug (Catalyst Engines) Each

ACDelco 41-993 Iridium Spark Plug – Indmar 5.7L Catalyst Engines

PLEASE NOTE: The ACDelco 41-993 Iridium Spark Plug has been discontinued and is no longer manufactured. The 41-993 has been superseded by the ACDelco 41-101 Iridium Spark Plug for applicable Indmar marine engine applications.

The ACDelco 41-993 Iridium Spark Plug was used in applicable Indmar 5.7L catalyst-equipped marine engines. Designed to provide reliable ignition performance and long service life, the 41-993 was a common spark plug used in Indmar gasoline marine engines equipped with catalytic exhaust systems.

Spark plugs are an important part of your boat's ignition system and should be inspected and replaced according to the manufacturer's recommended maintenance schedule. Worn or fouled spark plugs can contribute to hard starting, rough idle, hesitation, misfires, and reduced engine performance.

ACDelco 41-993 Has Been Discontinued

The ACDelco 41-993 spark plug was discontinued by ACDelco in 2026 and is no longer manufactured.

For applicable Indmar marine engine applications that previously used the ACDelco 41-993, the plug has been superseded by the ACDelco 41-101 Iridium Spark Plug by Indmar and GM.

If your Indmar owner's manual, service information, or existing spark plugs specify ACDelco 41-993, use the current ACDelco 41-101 replacement spark plug for applicable applications.

Indmar 5.7L Catalyst Engine Fitment

The ACDelco 41-993 Iridium Spark Plug was specified for applicable Indmar 5.7L gasoline marine engines equipped with catalytic exhaust systems.

Because Indmar used different spark plugs depending on engine model, production year, and catalyst configuration, always verify the correct spark plug for your specific engine before ordering a replacement.

For non-catalyst Indmar engines, the 41-993 is not the correct spark plug. Applicable non-catalyst Indmar engines may use the ACDelco MR43LTS Spark Plug instead.

ACDelco 41-993 Spark Plug Specifications

• Manufacturer: ACDelco
• ACDelco Part Number: 41-993
• Part Status: Discontinued
• Superseded By: ACDelco 41-101 Iridium Spark Plug
• Spark Plug Type: Iridium
• Application: Applicable Indmar 5.7L catalyst-equipped marine engines
• Spark Plug Gap: 0.059"
• 5.7L Installation Torque: 11 ft-lbs.
• Electrode Core Material: Copper
• Electrode Tip Material: Iridium
• Spark Plug Thread Size: 14mm
• Quantity: Sold Individually
• UPC: 808709617198

Iridium Spark Plugs for Indmar Marine Engines

Iridium spark plugs are designed to provide dependable ignition performance and durability in demanding engine applications. The fine-wire iridium center electrode helps provide consistent spark performance throughout the plug's service life.

Replacing worn spark plugs according to your Indmar engine maintenance schedule can help maintain:

• Smooth engine starting
• Consistent idle quality
• Reliable ignition under load
• Proper combustion
• Engine performance and throttle response
• Reduced risk of ignition-related misfires

Catalyst vs. Non-Catalyst Indmar Spark Plugs

It is important to determine whether your Indmar 5.7L engine is equipped with a catalytic exhaust system before selecting replacement spark plugs.

Catalyst-Equipped Indmar 5.7L Engines:
The ACDelco 41-993 was used in applicable catalyst-equipped applications and has now been superseded by the ACDelco 41-101 Iridium Spark Plug.

Non-Catalyst Indmar Engines:
Applicable non-catalyst engines may require the ACDelco MR43LTS Spark Plug instead.

Need Help Finding the Correct Indmar Spark Plug?

If you're unsure which spark plug your Indmar engine requires, contact us with your boat year, engine model, and engine serial number. Our team can help identify the correct spark plugs and ignition service parts for your application.

You can also visit the Bakes Resource Library and reference our Indmar Spark Plug & Spark Plug Wire Reference Chart for additional engine and ignition fitment information.

Looking for ACDelco 41-993? This spark plug has been discontinued and superseded by ACDelco 41-101 for applicable Indmar marine engine applications.