Honda Bf8D Bf20D Water Pump Impeller Replacement Repair Guide

Difficulty

Moderate

Steps

Time Required

                          30 minutes - 1 hour

Sections

Impeller
14 steps

Flags

BackHonda BF8D-BF20D
Full Screen
Options
History
Save to Favorites
Download PDF
Edit
Translate
Get Shareable Link
Embed This Guide
Notify Me of Changes
Stop Notifications

Introduction

What you need

Step 1

              Impeller

Shift the engine into reverse.

Shift the engine into reverse.

1024

Step 2

Optional: Remove the cotter pin from the propeller hub with pliers, then remove the bolt holding the propeller on. After that, remove the propeller.

Optional: Remove the cotter pin from the propeller hub with pliers, then remove the bolt holding the propeller on. After that, remove the propeller.

Step 3

Use a 10mm wrench to loosen the shift shaft connection located at the front of the extension case. It can be seen in the access hole.

Use a 10mm wrench to loosen the shift shaft connection located at the front of the extension case. It can be seen in the access hole.

Step 4

Remove the five 10mm bolts holding the lower unit to the extension case using either a wrench or ratchet.

Remove the five 10mm bolts holding the lower unit to the extension case using either a wrench or ratchet.

Step 5

Gently tap the lower unit/gear case with a rubber mallet until it becomes loose.

Gently tap the lower unit/gear case with a rubber mallet until it becomes loose.

Step 6

Carefully lower the lower unit/gear case down and remove it from the rest of the engine.

Carefully lower the lower unit/gear case down and remove it from the rest of the engine.

Step 7

Remove the four 10mm bolts with 10mm socket wrench.

Remove the four 10mm bolts with 10mm socket wrench.

Step 8

Lift the water pump/impeller housing off the drive shaft.
Remove the water pump impeller. Try to remember its exact position as that will be important during a later step.
Pay careful attention to the woodruff key holding the impeller on the shaft. You may need this later if your replacement kit does not come with one. The key has been marked in yellow so you know what part it is as it is small.

Lift the water pump/impeller housing off the drive shaft.

Remove the water pump impeller. Try to remember its exact position as that will be important during a later step.

Pay careful attention to the woodruff key holding the impeller on the shaft. You may need this later if your replacement kit does not come with one. The key has been marked in yellow so you know what part it is as it is small.

Step 9

Remove the bottom metal impeller housing plate.
Scrape the old gasket off.
Optional but recommended: With everything disassembled, inspect and clean corrosion/sand out of the lower unit/gearcase.

Remove the bottom metal impeller housing plate.

Scrape the old gasket off.

Optional but recommended: With everything disassembled, inspect and clean corrosion/sand out of the lower unit/gearcase.

Step 10

Open the replacement water pump/impeller kit.
Replace the base plate gasket.
Replace impeller housing O-ring.

Open the replacement water pump/impeller kit.

Replace the base plate gasket.

Replace impeller housing O-ring.

Step 11

Install the water pump/impeller into the housing in correct direction by pushing and rotating it so that all impeller blades face the same correct direction. All blades should be slightly bent to the right in the housing.
The woodruff key slot should be noted. This has been marked in orange to clarify the location.

Install the water pump/impeller into the housing in correct direction by pushing and rotating it so that all impeller blades face the same correct direction. All blades should be slightly bent to the right in the housing.

The woodruff key slot should be noted. This has been marked in orange to clarify the location.

Step 12

Hold the woodruff key in place with a pair of pliers. Slide the water pump/impeller housing down the shaft and align the woodruff key slot on the impeller with the woodruff key. Align the slot and key, then rotate it into place.
If this proves to be difficult, remove the metal impeller race from the plastic impeller housing and try again.

Hold the woodruff key in place with a pair of pliers. Slide the water pump/impeller housing down the shaft and align the woodruff key slot on the impeller with the woodruff key. Align the slot and key, then rotate it into place.

If this proves to be difficult, remove the metal impeller race from the plastic impeller housing and try again.

Step 13

Reinstall the 4 impeller housing bolts.
Grease the driveshaft and especially the splined section of the driveshaft with marine grade grease.
Reinstall the lower unit/gearcase into the engine. This may require you to rotate the shaft to allign the splines.
Reinstall the 5 10mm bolts that hold the lower unit/gearcase and tighten to 9 Foot-pounds of pressure. These bolts were the ones removed in step 4.
Reconnect the shift linkage.

Reinstall the 4 impeller housing bolts.

Grease the driveshaft and especially the splined section of the driveshaft with marine grade grease.

Reinstall the lower unit/gearcase into the engine. This may require you to rotate the shaft to allign the splines.

Reinstall the 5 10mm bolts that hold the lower unit/gearcase and tighten to 9 Foot-pounds of pressure. These bolts were the ones removed in step 4.

Reconnect the shift linkage.

Step 14

Shift the engine back into neutral.

Shift the engine back into neutral.

After shifting the engine back into neutral, the repair is complete.

Cancel: I did not complete this guide.

                                                                                      3 other people completed this guide.

Author

                                      with 2 other contributors

                    Christopher Phillippe

Member since: 01/29/2020

292 Reputation

                                      1 Guide authored                  



                       Badges:
                       7







                                                        +4 more badges

Team

                       Embry-Riddle Aeronautical University, Team S9-G4, Pinholster Spring 2020                        

                                                  Member of Embry-Riddle Aeronautical University, Team S9-G4, Pinholster Spring 2020 



                    ERAU-PINHOLSTER-S20S9G4                     


                                            5 Members                     


                                            1 Guide authored

didier bernard - Aug 26, 2021

Merci..!

Très pratique

Darrell Lyford - May 4, 2022

great directions for someone thats never done this. i viewed this guide and completed it like a pro. many thanks. DLyford Bangor, Maine

Bart De Craecker - Jul 29, 2022

Very clear, usefull “onepager” to replace the impeller of this Honda. Thank you very much !

Bart DC - Belgium

Cameron Bartlett - Aug 9, 2022

Great directions! Took me a minute to figure out to turn the propeller to shift into reverse. Thanks a bundle!

Pierre - Aug 24, 2022

Did the replacement as suggested. Still no steady stream just a dribble!? Maybe the missing broken rubber piece blocking the passage?

Introduction#

What you need#

Team#

Introduction

What you need

Team