Sierra 18-5907 Heavy-Duty Starter, 9 Tooth Clockwise, Replaces 50-72550A2 - GM & Ford Opposite Rotation Engines

The Sierra 18-5907 is a heavy-duty, no-core replacement starter built for opposite rotation GM and Ford marine engines. It is a top mount, rear entry starter with clockwise rotation and a 9 tooth drive gear, and it will also replace bottom mount standard rotation starters. This starter is designed for Mercruiser built 4 cylinder engines including the 165, 170, 180, 190, 470, 485, and 488, as well as Ford 302 CID and 351 CID engines. Note that it will not replace non-starter mounted solenoids -- it is intended for applications where the solenoid is mounted directly on the starter itself. The 18-5907 meets SAEJ1171 standards and pairs with the Sierra 18-5837 solenoid when a replacement solenoid is needed. It ships with no core required, simplifying installation for boat owners and marine technicians replacing a worn or failed starter. As with other Sierra electrical components, this starter is built to meet or exceed the performance of the original equipment part it replaces, making it a straightforward drop-in solution for the listed engine applications.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-5907
• Type: Starter
• Duty Rating: Heavy-Duty
• Core Required: No
• Rotation: Clockwise
• Tooth Count: 9 tooth
• Mounting: Top mount, rear entry
• Also Fits: Bottom mount standard rotation applications
• Compatibility Note: Will not replace non-starter mounted solenoids
• Voltage: 12 Volts
• Phase Type: Cranking
• Standard: SAEJ1171
• Replacement Solenoid: 18-5837
• Weight: 23.3 pounds
• Dimensions: 5 x 8 x 13 inches
• UPC: 030999875921

Fitment

• Opposite rotation GM & Ford engines (top mount, rear entry)
• Ford 302 CID and 351 CID engines
• Mercruiser built 4 cylinder engines: 165, 170, 180, 190, 470, 485, 488
• Also replaces bottom mount, standard rotation starter applications

Replaces (OEM)

• 50-72550A2
• 50-79604A3
• 50-97499A2
• 50-97499R4
• 50-72550R2
• 50-97499R3

Frequently Asked Questions

What engines does the Sierra 18-5907 starter fit? The 18-5907 fits opposite rotation GM & Ford engines, including Ford 302 CID and 351 CID engines, and Mercruiser built 4 cylinder engines: 165, 170, 180, 190, 470, 485, and 488.

Is the 18-5907 a top mount or bottom mount starter? It is a top mount, rear entry starter, and it will also replace bottom mount standard rotation starter applications.

Which direction does the 18-5907 starter rotate? Clockwise rotation, designed for opposite rotation GM and Ford engines with a 9 tooth drive gear.

Does the Sierra 18-5907 require a core exchange? No, the 18-5907 is sold with no core required.

What OEM part numbers does the 18-5907 replace? The 18-5907 replaces 50-72550A2, 50-79604A3, 50-97499A2, 50-97499R4, 50-72550R2, and 50-97499R3.

Will the 18-5907 work with any solenoid? It will not replace non-starter mounted solenoids; the matching replacement solenoid is the Sierra 18-5837.

How much does the 18-5907 starter weigh? This starter weighs 23.3 pounds.

What are the dimensions of the 18-5907 starter? The 18-5907 measures 5 x 8 x 13 inches.

What voltage is the 18-5907 starter rated for? 12 Volts, with a cranking phase type.

Does the 18-5907 meet any industry standards? Yes, the 18-5907 meets the SAEJ1171 standard.

Can the 18-5907 be used on Ford-powered I/O boats? Yes, it fits 302 CID and 351 CID Ford engines in opposite rotation applications.

Is the 18-5907 a heavy-duty starter? Yes, the 18-5907 is a heavy-duty rated starter designed for marine I/O and Mercruiser electrical systems.