RD-17 water pump update PN

[trex014]

I see that a new style of impeller is out there for an updated water pump housing for say a ’55 25hp Johnson RD or similar motor.

Anyone know the part number for the new style of housing? I have yet to stumble upon it.

Thanks

[frankr]

Part number for the complete new style water pump kit is 391741. Sorry, I don’t have the numbers for individual parts.

EDIT: Um, better verify that kit. I’m not sure it will work in your old RD.

• This reply was modified 4 years ago by frankr.

[Mumbles]

I’m showing 379774 (sierra 18-3006) as the P/N for the complete kit with housing for ’55 and 391741 being used on ’74 – ’76 40 horse motors. I’ve never seen or heard of an updated housing or impeller for these motors but I could be wrong. You wouldn’t be thinking of the upgraded pump kits for the 5.5-6-7.5 horse motors would you?

[trex014]

I am getting all this from MARINEENGINE.COM fyi. I’m working on a ’55 25hp though the earliest marine engine parts manual breakdown is a ’57 35hp which uses the same original impeller currently 0775521 and original housing 0303831.

On the impeller page it says “see note” which mentions an updated impeller and water pump housing. Though it only gives the number for the updated impeller (PN# 0763982) but not a housing PN.

If my digging is correct I believe the updated kit with housing is #395270. It is has the updated impeller as well. I believe this would fit the big twin lower units even though it has 4 bolts instead of the original housing’s 3. I cannot remember if those lower units are drilled and tapped for that 4th hole.

[Mumbles]

I think I know what’s going on here with the ‘updated kit’. The 763982 impeller is used in ’78 and later 25-30-35 horse motors along with the plastic four bolt housing in the 395270 kit? That impeller might use a wedge style drive key so some filing might be necessary on the ’55 driveshaft to get it to work.

[frankr]

Mumbles wrote:

I’m showing 379774 (sierra 18-3006) as the P/N for the complete kit with housing for ’55 and 391741 being used on ’74 – ’76 40 horse motors. I’ve never seen or heard of an updated housing or impeller for these motors but I could be wrong. You wouldn’t be thinking of the upgraded pump kits for the 5.5-6-7.5 horse motors would you?

391741 for 40hp 74-76 is what I came up with, thinking it would fit the old RD’s. But then I changed my mind, thinking the drive shaft diameter is different. True or not true?

[outboardnut]

sierra 18-3006 is the impeller only
this is from a 1999 Napa catalog

• This reply was modified 4 years ago by outboardnut.
• This reply was modified 4 years ago by outboardnut.

[frankr]

That is true for the original pump. But I thought the question was for the new style pump kit with plastic housing and stainless steel liners, if one exists or the RD models.

This is getting complicated.

[outboardnut]

I do believe Mumbles is spot on about complete kit (0379767 / 0379774 )
except – I do not remember ever running across 317078 – Impeller Key

[outboardnut]

Impeller Key 317078

• This reply was modified 4 years ago by Mumbles.

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