Glo — Blue Impeller Pin — GLO-421

The Globe Marine Products #421 Run-Dry Impeller is a flexible raw water pump impeller designed for compatible marine engine cooling pumps. Built from Globe’s blue self-lubricating elastomer compound, this impeller is intended for raw water and coolant circulation applications where the pump, engine manual, or existing impeller confirms GLO-421 or 421.

This is a pin-drive impeller, meaning the pump shaft uses a small drive pin that engages the slotted hub of the impeller to prevent slipping during pump operation.

Key Features

• Globe Marine Products Run-Dry raw water pump impeller.
• Part number: GLO-421.
• Common listing reference: Globe #421.
• Blue elastomer construction for raw water / coolant pump service.
• 6-blade flexible impeller design.
• Pin-drive / slotted-hub configuration.
• Designed for compatible marine engine raw water cooling pumps.
• Run-dry protection reference up to 15 minutes under suitable conditions.
• Helps maintain cooling water flow through the engine, heat exchanger, and exhaust system.
• Typically supplied with paper faceplate gasket and sealing O-rings where packaged as a kit.

Technical Specifications

• Impeller type: flexible raw water pump impeller
• Material: Globe blue run-dry elastomer
• Blade count: 6
• Drive style: pin drive / slotted inner hub
• Outer diameter: 1-9/16 in. / 39.7 mm
• Width / depth: 3/4 in. / 19 mm
• Shaft inner diameter: 3/8 in. / 9.5 mm
• Primary use: marine raw water and coolant pump applications
• Not for: diesel or oil transfer pump service

Engine & Pump Compatibility

Common application context includes compatible compact marine diesel engines and raw water pumps where this impeller size and drive style are specified, including:

• Compatible Jabsco pump applications using the listed cross-reference group.
• Compatible Johnson Pump applications using 09-806B-1.
• Select Volvo Penta compact diesel applications where listed.
• Select Yanmar compact diesel applications where listed.
• Select Sherwood and Sierra replacement applications where listed.
• Yamaha applications using the matching Yanmar-style reference where specified.

Use this impeller only where the pump model, engine model, serial number, shaft size, impeller width, outer diameter, and drive style match the application.

Fitment Notice

Confirm fitment by pump model, engine model, existing impeller number, shaft diameter, hub drive style, impeller width, and outer diameter before ordering. Flexible impellers can look similar but may differ in blade count, hub style, shaft size, depth, and gasket requirements.

This impeller is for compatible 3/8 in. pin-drive / slotted-hub pump applications. Do not substitute it into spline-drive, key-drive, or larger pump housings unless the parts manual confirms compatibility.

When This Part Needs Replacement

Replace the impeller at least once per season, during scheduled cooling system service, after dry running, after overheating, after long storage, or whenever cooling water flow is weak.

Replacement is also recommended if the blades are cracked, stiff, swollen, permanently bent, missing, heat-glazed, or damaged. A failed raw water impeller can cause overheating, exhaust hose damage, reduced cooling flow, and broken rubber blades traveling downstream into the heat exchanger or oil cooler.

Installation Notes

Inspect the pump body, cam, wear plate, cover plate, gasket surface, and drive pin before installing the new impeller. Lubricate the impeller blades with glycerin, soapy water, or approved impeller lubricant before installation.

Twist the blades in the correct direction as the impeller is inserted into the pump housing. Replace the faceplate gasket or O-ring as required, then confirm strong water discharge after startup. Even with run-dry protection, avoid operating the raw water pump without water.

Alternate / Cross-Reference Part Numbers

• Globe GLO-421 — primary part number
• Globe #421 — common listing reference
• Jabsco 4528-0001 — cross-reference reference; verify by pump model
• Jabsco 22429-0001 — cross-reference reference; verify by pump model
• Jabsco 8293-0001 — cross-reference reference; verify by pump model
• Johnson Pump 09-806B-1 — cross-reference reference; verify by pump model
• Volvo Penta 3586494 — cross-reference reference; verify by engine and pump model
• Volvo Penta 875807 — cross-reference reference; verify by engine and pump model
• Volvo Penta 807369 — cross-reference reference; verify by engine and pump model
• Volvo Penta 833550 — cross-reference reference; verify by engine and pump model
• Volvo Penta 876689 — cross-reference reference; verify by engine and pump model
• Volvo Penta 3580029 — cross-reference reference; verify by engine and pump model
• Volvo Penta 803729 — cross-reference reference; verify by engine and pump model
• Volvo Penta 876554-7 — cross-reference reference; verify by engine and pump model
• Yanmar 104211-42070 — cross-reference reference; verify by engine and pump model
• Yanmar 104211-42071 — cross-reference reference; verify by engine and pump model
• Sherwood 9979 — cross-reference reference; verify by pump model
• Sierra Marine 18-3079 — cross-reference reference; verify by pump model
• Yamaha 104211-42070 — cross-reference reference; verify by application

Parts Desk Insight

The key fitment details on this impeller are the 1-9/16 in. outer diameter, 3/4 in. width, 3/8 in. shaft size, and pin-drive hub. Match those dimensions and the pump model before ordering. The blue Globe compound adds run-dry protection, but proper installation, lubrication, and pump inspection are still important for reliable cooling performance.

Shipping: Ships same or next day for fast Canada wide shipping. ⚓