Raw Water Pump Teardown

[rkmason]

Has anyone done a complete teardown of a Johnson Pump F6B-9 crank-driven raw water pump? How does the driveshaft come out? Is it pressed out leaving the water seals and driveshaft bearings in the housing? Thanks

[Sodar]

I took my pump into the local guy last year with new bearings, seals, impleller, etc. He said "just buy a new pump" So, I figured why not destroy this one if I am going to have buy another one!?!

To answer your question, yes the shaft is pressed in. I had a problem when I pressed mine out, half the bearing stuck to the shaft. I ended up needing to get a bearing puller to get it off. I ended up getting the whole thing rebuilt and mounted, but it had an ugly wobble to it, so I ended up just buying a new one for $130.

[Jim@BAWS]

Don't waste your time. 3 hexhead screws and one at the base of the pump and you are done. A rebuild kit with a bearing kit is about $60

No guarentee that it will work

Just buy a new pump. A new impeller comes with it

Jim@BAWS

[beef]

Originally Posted by Jim@BAWS

Don't waste your time. 3 hexhead screws and one at the base of the pump and you are done. A rebuild kit with a bearing kit is about $60

No guarentee that it will work

Just buy a new pump. A new impeller comes with it

Jim@BAWS

+1

I researched the rebuild this past summer and just decided to buy a new pump. Installed it in 15 minutes and back to skiing. Done.

[rkmason]

I already have a new replacement pump; just considering a total rebuild of my old pump so I can start swapping the two periodically. I hate to just throw the old one away if I can rebuild it. Maybe I'll take a shot at the rebuild and if it gets messed up THEN I'll toss it.

[rkmason]

Well, I went ahead and rebuilt my old raw water pump just to see if I could. I have it back on the boat and it runs fine w/no leaks.

The tricky bit was pushing the driveshaft and bearings out of the pump housing without damaging anything. When Johnson builds these pumps they make sure the bearings stay in the pump housing by hammer punching the bearing housing OD in one spot. I drilled that hammered spot out to help relieve the pressure and the bearings and shaft came out without much trouble.

I found the SKF brand bearings and an near-OEM equivalent water seal at an online bearing supply house. My total parts cost was about $20. If you are willing to use Chinese no-name brand bearings the parts cost can be reduced to about $10.

To retain the bearings I drilled and tapped three holes around the bearing housing for very short 8-32 setscrews. Now I have a pump I can easily rebuild the next time.

So you can rebuild your raw water pump yourself if you are so inclined. Most people will still probably just buy a new replacement, but where's the fun in that?

[Snipe]

Originally Posted by Jim@BAWS

Don't waste your time. 3 hexhead screws and one at the base of the pump and you are done. A rebuild kit with a bearing kit is about $60

No guarentee that it will work

Just buy a new pump. A new impeller comes with it

Jim@BAWS

I'm with Jim

[TMCNo1]

Thanks for the effort and the information for those with Johnson pumps!

[Prostar Rich]

I don't mean to get off subject but how long does the raw water pump last? What kind of life did you guys get before rebuilding or replacing?

Thanks,
Prostar Rich

[Slinkyredfoot]

With the exception of replacing impellers over the years, I finally totally rebuilt my original last winter for the first time, a 1979 PCM.