Sierra 18-5603-1 Noseless Starter, Top Mount Rear Entry, Replaces 573001, GM and Ford Standard Rotation Engines

The Sierra 18-5603-1 is a noseless, top mount, rear entry starter built for standard rotation GM and Ford marine engines. It turns CCW (counterclockwise) and is engineered as a direct replacement for OEM part number 573001, giving boat owners a straightforward swap when the original starter fails or needs replacement. This starter can also be used in place of Sierra part 18-5908, making it a flexible option for shops and owners servicing multiple engine setups that call for either part.

Construction is steel, and the unit is rated at 1.2 KW with a three phase design. At 10.4 pounds, it matches the physical demands of inboard cranking duty on standard rotation blocks. It is backed by a 90 day warranty, giving buyers confidence in fit and function from install.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-5603-1
• Product Type: Starter
• Starter Type: Noseless, top mount, rear entry
• Rotation: CCW (standard rotation)
• Engine Compatibility: GM and Ford engines
• Interchangeable With: Sierra 18-5908
• Material: Steel
• Wattage: 1.2 KW
• Phase Type: Three Phase
• Weight: 10.4 pounds
• UPC: 808282379087
• Warranty: 90 days

Fitment

• Standard rotation GM engines
• Standard rotation Ford engines

Replaces (OEM)

• 573001

Frequently Asked Questions

What engines does the Sierra 18-5603-1 starter fit? The Sierra 18-5603-1 is built for standard rotation GM and Ford marine engines, turning CCW (counterclockwise) in a top mount, rear entry configuration.

Is the Sierra 18-5603-1 a match for an OEM 573001 starter? Yes, the 18-5603-1 replaces OEM part number 573001, making it a direct swap for engines originally fitted with that starter.

What does noseless mean for this starter? Noseless describes the housing style of the Sierra 18-5603-1, which mounts at the top of the engine and enters at the rear rather than using a front drive nose extension.

Can the 18-5603-1 be used instead of a Sierra 18-5908 starter? Yes, the Sierra 18-5603-1 can be used in place of Sierra part 18-5908 on applicable standard rotation GM and Ford engines.

Which direction does this starter rotate? The Sierra 18-5603-1 turns CCW, meaning it is built for standard rotation engines, not reverse rotation applications.

How much does the Sierra 18-5603-1 starter weigh? This starter weighs 10.4 pounds.

What is the mounting style of the 18-5603-1? The Sierra 18-5603-1 is a top mount, rear entry starter with a noseless housing design.

What material is the Sierra 18-5603-1 starter made from? The 18-5603-1 starter is made of steel.

What is the power rating of this starter? The Sierra 18-5603-1 is rated at 1.2 KW.

Is the 18-5603-1 a three phase or single phase unit? The Sierra 18-5603-1 is a three phase starter.

What warranty covers the Sierra 18-5603-1 starter? A 90 day warranty covers the Sierra 18-5603-1 starter.

What is the UPC for the Sierra 18-5603-1 starter? The UPC for the Sierra 18-5603-1 starter is 808282379087.