50-58788A3 Aftermarket Mercruiser Starter Motor | Sawley's Select Marine Parts

🔧 Product Description

Aftermarket Mercury/Mariner outboard starter motor - Part Number: 50-58788A3

A ten-tooth 12-volt starter for early Mercury and Mariner inline four-cylinder two-stroke outboards. It is principally used on Model 650, 800 and 850 engines from the late 1960s and 1970s. The supplied title's MerCruiser classification does not match the verified outboard application.

This historical Mercury starter is no longer available as a new OEM assembly, making a correctly matched marine aftermarket replacement the normal service option.

⚙️ Key Features

• 12V outboard starter motor

• Ten-tooth starter drive

• Suitable for early Mercury inline-four flywheel arrangements

• Complete replacement motor and drive assembly

• Marine-duty corrosion-resistant construction

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• 50-58788A3 → Supersedes 50-58788

• OEM assembly is no longer serviced as a new Mercury part

OEM / Related Numbers:

• Mercury: 50-58788A3

• Mercury: 50-58788

• Mercury: 50-57465A1

• Mercury: 50-57867A1

• Mercury: 50-64975

• Mercury: 50-72467

Aftermarket / Verified Equivalents:

• Sierra: 18-5636

• ARCO Marine: 5377

• Mallory: 9-15009

• Mallory: 9-15029

🚤 Compatibility

Commonly used on:

• Early Mercury and Mariner inline four-cylinder two-stroke outboards

Typically suits:

• Engine models:

• Mercury 650 / 65HP four-cylinder

• Mercury 800 / 80HP four-cylinder

• Mercury 850 / 85HP four-cylinder

• Corresponding Mariner models fitted with the same ten-tooth starter

• HP Range: 65HP-85HP

• Engine Type: Inline four-cylinder carburetted two-stroke outboard

• Year Range: Approximately 1969-1977

• Serial Guidance:

• 650: commonly serial 2803562-3293183

• 800/80: commonly serial 2559001-3493912

• 850: commonly serial 3493913-4366801, with additional international serial groups

🔌 Function

The starter drives the flywheel during engine start-up and disengages automatically once the engine fires.

Common signs of failure:

• No starter response

• Slow cranking or excessive current draw

• Starter spins but does not engage

• Grinding caused by damaged pinion or ring-gear teeth

• Intermittent operation from worn brushes or bushings

📦 Condition

• Brand-new aftermarket starter motor

• Supplied as a complete ten-tooth assembly

• Verify the original starter number and flywheel engagement before installation