Changing Impeller – How hard is it?

[MARC BOUCHER]

I’ve been a collector for about 12 years and haven’t changed an impeller yet. However, I recently acquired a 1952 Evinrude 25 hp outboard that I would love to use this summer with my son. Prior to trying to start it I am planning on changing out the lower gear oil and swapping plugs. I’ve read somewhere that it is wise to put some Marvel Mystery oil in the chambers prior to my first pulls. The other main thing I have heard is that I should probably change out the impeller – however, I don’t know what is all involved… Is this something a non-super-mechanical guy can do? Or is this reserved for just the ‘real’ mechanics?

Anything else I should be checking prior to that first pull? I don’t know how long the motor has been sitting, but it looks like it is in GREAT shape.

Thanks for any help you can give me!

-Marc

Boats: '47 Dunphy, '64 Starcraft
Motors:
'53 Evinrude 25; '54 Evinrude 7.5; '55 Evinrude 7.5; '56 Evinrude 30 Lark; '56 Evinrude 16; '58 Johnson 18; '60 Evinrude 10; '64 Evinrude 40

[crosbyman]

Marc as a member get the johnson maintenance manual

IN….

MEMBERS ONLY section INNER SANCTUM…..LIBRARY…. GARRY SPENCER’S DROP BOX…. find the JOHNSONMAINT MANUAL red book and download it

it covers your engine all section incl the lower end

impeller swaps are easy to do .. basically

go on utube… lots of videos

Joining AOMCI has priviledges 🙂

• This reply was modified 3 years ago by crosbyman.

[need2fish]

If you’re going to go to the trouble of dropping the lower unit, consider replacing the gear case seals (prop shaft, drive shaft, clamshell “string” seal, the shift shaft o-ring and the clutch yoke pivot seal).

You’ll also be able to inspect the lower end of the drive shaft and the whole prop shaft).

The procedure is very easy – just document what comes off and in which order and take photos.

The only special tool needed is a seal puller — I picked mine up at an auto parts store (Pep Boys, Advance, Napa, Autozone) for 10 bucks.

[crosbyman]

marc… see links to owner manual and parts for your 1952 25hp 🙂

https://www.aomci.org/forums/topic/1952-johnson-25hp/

Joining AOMCI has priviledges 🙂

[MARC BOUCHER]

You guys are the best. You have given me courage to try it! Thanks for the links to the manual!!!!

One last related question though… Should I just try to start it and see if water comes out (just in case the impeller is still good) or does it make more sense to just change it before I even try to start it?

Thanks again!
Marc

Boats: '47 Dunphy, '64 Starcraft
Motors:
'53 Evinrude 25; '54 Evinrude 7.5; '55 Evinrude 7.5; '56 Evinrude 30 Lark; '56 Evinrude 16; '58 Johnson 18; '60 Evinrude 10; '64 Evinrude 40

[crosbyman]

thank mumbles our librarian.. book keeper and F.Robb

start it if you want for a 30 seconds but anyway you will need a new impeller …just in case ….

Joining AOMCI has priviledges 🙂

• This reply was modified 3 years ago by crosbyman.
• This reply was modified 3 years ago by crosbyman.

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