International Fuel Hand Primer Pump With Gasket 489944C91 for 1971-1980 Scout II Diesel 633 633T

International Fuel Hand Primer Pump With Gasket 489944C91 for 1971-1980 Scout II Diesel 633 633T

This fuel primer pump is engineered as a direct replacement for the 1971-1980 Scout II Diesel 633 633T. Manufactured to meet or exceed OEM specifications, it delivers reliable performance in demanding conditions. Each unit is tested for fuel flow, pressure rating, and durability before leaving the factory to ensure consistent quality across every order.

Vehicle Compatibility

Replaces OEM Part Numbers

489944C91 • 1971-1980

Signs You Need a Replacement

If your equipment is showing any of these symptoms, the fuel pump may be the cause:

• Primer bulb stays flat — The internal check valves are worn and can’t pull fuel from the tank. Replace the primer pump to restore fuel flow.
• Air bubbles in the fuel line — A worn primer pump allows air to enter the system through the shaft seal or housing crack.
• Engine hard to start after filter change — After replacing the fuel filter, the system needs to be primed. If the primer bulb doesn’t firm up, the pump is likely faulty.

Bleeding the System

After installing the new primer pump, pump the bulb until it becomes firm. Crack open the fuel line at the engine end and pump until fuel flows out bubble-free. Tighten the fitting and pump the bulb a few more times to confirm it stays firm. Start the engine and let it idle for a minute. If the primer bulb goes soft after the engine stops, check for air leaks at all connections.

Frequently Asked Questions

Can I cross-reference 489944C91 with 1971-1980?
Yes. Both 489944C91 and 1971-1980 are interchangeable OEM numbers for this part. They refer to the same component with the same specifications, just different part number revisions.

How do I check if my engine code (SD33) matches?
The engine code is stamped on a metal tag attached to the engine block, usually near the timing belt cover or on the cylinder head. Compare the code you find with the list above. Engine codes are 3 to 6 characters long.

My vehicle is a 1971 model – is it covered?
The compatibility range for this part includes 1971-1980. The 1971 model year falls within this range, but verify the engine code and body type match. Mid-year production changes sometimes mean two vehicles from the same model year use different parts.

How do I bleed the fuel system after replacing the primer pump?
Pump the primer bulb until it becomes firm. Then crack open the fuel line at the engine end and pump until fuel flows out bubble-free. Tighten the fitting, pump the bulb a few more times to confirm pressure holds, then start the engine.

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