Johnson Pump 01-42389 Cam Plate for F4B Pumps
The Johnson Pump 01-42389 is a brass cam plate (1/1 ratio) for the F4B series of engine-driven raw water pumps, including the F4B-4, F4B-8, and F4B-9 pump families. The cam controls how the impeller flexes as it rotates past the pump housing, and a worn or cracked cam is a common cause of reduced flow or premature impeller wear.
This cam plate also fits the Johnson F4B pumps used on a range of Volvo Penta engines, including the MD2030, MD2040, D1-30A through D2-75C, and AQ60F through MD20B series. It is used together with Johnson cam screw 01-46794-04 and cross-references to Jabsco cam plate 10818.
Key Features
- Brass construction for corrosion resistance
- 1/1 cam ratio matched to F4B pump housings
- Direct fit for genuine Johnson F4B service kits
Applications
- Johnson F4B-4, F4B-8, and F4B-9 raw water pump rebuilds
- Volvo Penta MD2030, MD2040, D1-30A through D2-75C, and AQ60F through MD20B engine cooling pumps
Specifications
- Material: brass
- Cam ratio: 1/1
- Width: 40mm
- Depth: 22mm
- Used with: Johnson cam screw 01-46794-04
- Cross-reference: Jabsco 10818 cam plate
Frequently Asked Questions
Q: What pumps does this cam plate fit?
Johnson F4B-4, F4B-8, and F4B-9 series raw water pumps, including the versions used on many Volvo Penta engines.
Q: What material is it made from?
Brass.
Q: Is this the same as Jabsco 10818?
It's a direct cross-reference to the Jabsco 10818 cam plate for the same pump family.
Q: Does it include the cam screw?
No — this is the cam plate only. It's used with Johnson cam screw 01-46794-04, sold separately.
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