Pump Sizes F35 - F95

Product Type(s) : Flexible Impeller Pumps - Engine Cooling
Description :

SPX FLOW Johnson Pump Marine is one of the leading original equipment pump suppliers to the largest manufacturers world-wide of inboard engines. Engine cooling pumps, the F-series, are available in several different styles and sizes to satisfy different cooling system needs. Flanged pumps which mount directly to the engine and crank shaft pulley mounted pumps are available for a wide variety of engines.

Both flange mounted and pulley driven pedestal pumps can be used to provide cooling with a maximum of ease and flexibility.




  • Limited 3 Year Warranty
  • Self-priming, a dry pump can lift water up to as much as 3 meters. Thus a flexible impeller pump being used for engine cooling does not need to be located below the water line or manually primed.
  • Flexible impeller pumps can pass fairly large solids without clogging or damaging the pump. This reduces the need for filtering the incoming fluid.
  • For general raw or fresh water applications, the standard long-lasting neoprene rubber impeller is used. All flexible impeller pumps is that they cannot be permitted to run dry for more than 30 seconds. Both the impeller and the seals depend upon the water for lubrication and will soon fail if run dry.
  • Wear parts are easily replaceable
  • Service kits are available for all standard models.
  • Flange Mounted Pumps (F4B-9, F7B-9, F9B-9)
  • Crank Shaft Pulley Mounted Pumps (F6B-9)
  • Belt/Pulley Driven Pedestal Pumps (F7B-8, F8B-3000)
  • Pump ports available from 3/8" to 2 1/2"
  • Capacity up to 625 liters/min (9900 gal/hr)


See this product in the Johnson Pump Marine Catalog:  US ‖ GB  ‖ DE ‖ ES ‖  FI ‖  SV

Theory of Operation




Flexible impeller pumps, F-series, provide an efficient solution to most raw water pumping needs. The primary advantage of a flexible impeller pump is its self-priming ability. As the vanes of the impeller are depressed and rebound, they create their own vacuum drawing fluid into the pump.


Pump Mounting


Flanged pumps are normal pumps produced in high volumes, customer designed for flange-mounting at a power take off of the engine. Different types of drives can be used but mainly gears or any type of driving members are used.



These pumps are designed for direct installation on the engine crank shaft pulley. Max. revs. 5.000 per minute. To prevent the pump from rotating, a torque bracket from the fastening point on the pump body to a suitable point on the engine has to be used.



Pulley driven pedestal mounted pumps are used when a free driving pulley is available on the engine. Two different types of pedestal mounted pumps are supplied:

  • FB-8 BSP/ FB-8007 NPT

A range of bronze pumps in compact design. Ideal as cooling water pumps in marine engines. Available in sizes from ⅜" to 1½", all with permanently lubricated double ball bearings and mechanical seal.

  • FB-3000 BSP OR FLANGE/ FB-3007 NPT

A range of extra heavy duty pedestal mounted pumps excellent for cooling purpose in commercial vessels. The design means separate bearing housings with permanently lubricated double ball bearings, mechanical shaft seal for extended service life. Wetted parts as wear plate, cam and endcover are easily replaceable.



Engine Cooling – Raw Water Handling

Different Types of Cooling Systems




Fresh Water Handling

For circulation of the internal, closed, fresh water circuit of the cooling system SPX FLOW Johnson Pump can
offer a number of alternatives in its DC driven Circulation Pump series (see Circulation Pumps page).

It is also common to use a flexible impeller pump for this purpose if it is located on the cold side of the system
(max. 55°C/ 131°F ). Other types of belt-driven centrifugal pumps may also be useful. The closed circuit normally transfers heat from the engine to the heat exchanger. The liquid is a water and anti-freeze mixture.



The required output of the cooling pump – raw water as well as fresh water handling – is related to:

  • Engine size and type (gasoline or diesel)
  • Type of cooling system (size of heat exchanger)
  • Water cooled engine oil, reverse gear, exhaust system

Contact your local dealer for more information, or for indirect cooling systems your supplier of heat exchangers.


Raw Water Cooled Engines


Fresh Water Cooled Engines


Capacity Range

(based on water at 20˚C/68˚F)


Vacuum Valve - Siphon Breaker

A vacuum valve is an inexpensive form of insurance against water intrusion in an engine, which could lead to expensive repairs. The maximum ambient temperature should not exceed 60ºC (140ºF).

The valve opens at a pressure which is equivalent to 30-50mm (7.47-12.45 mbar) Water Column. The materials used are resistant to sea water, fresh water and to glycol compounds in appropriate concentrations. Avoid exposing the valve to oil and grease. If it has been in contact with such substances, please clean or replace it.

  • Non corrosive
  • Easy to install
  • Does not leak
  • High quality plastic
  • 5 spud sizes



Part numbers

Part No. Description
09-47316-01 Vacuum Valve 12 mm
09-47316-02 Vacuum Valve 16 mm
09-47316-03 Vacuum Valve 19 mm
09-47316-04 Vacuum Valve 22 mm
09-47316-05 Vacuum Valve 25 mm
09-47316-06 Service Kit Vacuum Valve


See the Original Impeller Kits page for original replacement impellers.

See the Impeller Tools page for impeller removal tools.