NGK BPR6EFS Spark Plug, Replaces Mercury Marine 33-816336Q, Fits MerCruiser, Volvo Penta, OMC Inboard Engines

The NGK BPR6EFS is a standard marine spark plug built around a solid copper core for efficient heat dissipation and reliable ignition performance. It uses a threaded, removable-nut terminal for easy installation and removal, and is engineered to promote longer service life and consistent operation in marine inboard applications. The BPR6EFS is designed to fit most popular inboard engines, including Indmar, Marine Power, MerCruiser, OMC, Redline, and Volvo Penta powerplants, as well as Boston Whaler jet boat engines. It carries a 14mm shell thread with a tapered seat, a 5/8 inch (16mm) hex, and an 18mm (.709 inch) reach, with a factory-set gap of.031 inch (0.8mm). The center electrode uses a projected, standard 2.5mm nickel-tipped design with a copper core, paired with a standard nickel ground electrode, giving a heat range of 6 and a rated service life of 30,000 miles. This plug is a direct replacement for Mercury Marine 33-816336Q and is sold individually, so be sure to order the correct quantity for your engine's cylinder count. Always check your engine and maintenance manual to confirm this is the correct spark plug for your application, and only install plugs recommended by your engine's original equipment manufacturer -- using the wrong plug can reduce performance, lower fuel economy, or cause engine damage.

Specifications

• Brand: NGK
• Manufacturer Part Number: BPR6EFS
• Shell Thread Size: 14 millimeters
• Thread Pitch: 1.25 millimeters
• Seat Type: Tapered
• Resistor: Yes, 5K Ohm
• Reach: 18 millimeters (0.709 inch)
• Hex Size: 5/8 inch (16 millimeters)
• Terminal Type: Removable Nut
• Spark Plug Gap: 0.031 inch (0.8 millimeters)
• Center Electrode: Nickel tip, copper core, standard 2.5 millimeters, projected
• Ground Electrode: Nickel, standard
• Heat Range: 6
• Longevity: 30,000 miles
• Quantity: 1 (sold individually)
• Torque Spec, Cast Iron Cylinder Head: 18 to 25.3 lb-ft
• Torque Spec, Aluminum Cylinder Head: 18 to 21.6 lb-ft
• UPC: 087295136232
• Weight: 0.15 pounds

Fitment

• Indmar inboard engines
• Marine Power inboard engines
• MerCruiser inboard engines
• OMC inboard engines
• Redline inboard engines
• Volvo Penta inboard engines
• Boston Whaler jet boat engines

Replaces (OEM)

• Mercury Marine 33-816336Q

Frequently Asked Questions

What engines does the NGK BPR6EFS spark plug fit? The NGK BPR6EFS is designed to fit most popular marine inboard engines, including Indmar, Marine Power, MerCruiser, OMC, Redline, and Volvo Penta engines, as well as Boston Whaler jet boat engines.

Is the BPR6EFS a direct replacement for Mercury Marine 33-816336Q? Yes, the NGK BPR6EFS spark plug replaces Mercury Marine part number 33-816336Q.

What is the thread size and reach of this spark plug? The BPR6EFS has a 14 millimeter shell thread with a tapered seat and an 18 millimeter (0.709 inch) reach.

What is the factory gap setting on the NGK BPR6EFS? This spark plug is set to a gap of 0.031 inch (0.8 millimeters) from the factory.

Does the BPR6EFS have a resistor? Yes, the NGK BPR6EFS includes a resistor rated at 5K Ohm.

What materials are used in the electrodes? The BPR6EFS uses a nickel-tipped center electrode over a copper core, along with a standard nickel ground electrode, for efficient heat dissipation and reliable spark performance.

How many spark plugs come in a purchase? The NGK BPR6EFS is sold individually, one spark plug per unit, so order enough to match your engine's cylinder count.

What is the heat range and expected service life of this plug? The BPR6EFS has a heat range of 6 and a rated longevity of 30,000 miles under normal use.

What torque should be used when installing the BPR6EFS? Torque the NGK BPR6EFS to 18-25.3 lb-ft in a cast iron cylinder head, or 18-21.6 lb-ft in an aluminum cylinder head.

What size wrench or socket is needed to install this spark plug? The BPR6EFS uses a 5/8 inch (16 millimeter) hex, and the terminal is a removable nut type.

How do I know if the BPR6EFS is the correct plug for my engine? Always check your engine's maintenance manual before installing the NGK BPR6EFS, since using the wrong spark plug can reduce performance, lower fuel economy, or damage your engine.