Shredded impeller

D

Dialtone75

Cadet

Joined

Jul 17, 2009

Messages

13

• Jul 17, 2009

• #1

1969 25hp Johnson outboard....I brought this back from the dead and replaced the impeller which had a broken vein on it. Started it up and put the water earmuffs on it but no water was discharging. Took the lower unit apart and found the impeller totally shredded. Now please bear with me but here is my noob question. Am I supposed to lube the impeller when putting a new one in? I have a manual and almost positive I put it back together properly. Wonder how it went out so fast???

 

ScottinAZ

Senior Chief Petty Officer

Joined

Jun 25, 2009

Messages

742

• Jul 17, 2009

• #2

Re: Shredded impeller

not an expert here, but when I did mine, I checked the impeller bore for burrs, rubber chunks from the old impeller, and other "nasties" I then lubed the impeller with vaseline, and reinstalled. I figured that a wee bit of rubber safe lube wouldnt hurt a thing.

 

E

ezeke

Supreme Mariner

Joined

Sep 19, 2003

Messages

12,532

• Jul 17, 2009

• #3

Re: Shredded impeller

It probably ran dry - it only takes seconds to destroy a new impeller like that. When you put the new one in you can lubricate the housing which will help with the installation.

The important thing is to have water in the pump before you start the motor. To do that you need to have the motor in water deep enough to actually cover the pump and you need to be sure that the air bleed at the inside top of the water pump housing is clear.

 

F

fix_it

Seaman Apprentice

Joined

Aug 31, 2008

Messages

38

• Jul 17, 2009

• #4

Re: Shredded impeller

You said that you started it and then put the muffs on. If you did that, then there is the problem. You always put the muffs on (with the water turned on) and then start it. If not you can (and probably will) damage the impeller.

 

cougar1985

Lieutenant Junior Grade

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Oct 7, 2005

Messages

1,023

• Jul 18, 2009

• #5

Re: Shredded impeller

are you absoletly sure the 25 can be cooled by muffs?my 1970 33 evinrude has to be put in a barrel!

 

tashasdaddy

Honorary Moderator Emeritus

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Nov 11, 2005

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51,019

• Jul 18, 2009

• #6

Re: Shredded impeller

neither of those motors will run on muffs. they must be submerged 1/2 way up the leg in a barrel. the red line is the water pickup, the red line is the exhaust. the Green is the exhaust relief ports, that you should get a mist or droplets out of. this is your tale tell that the impeller is pumping.

 

cougar1985

Lieutenant Junior Grade

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Oct 7, 2005

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1,023

• Jul 18, 2009

• #7

Re: Shredded impeller

tashasdaddy said:

neither of those motors will run on muffs. they must be submerged 1/2 way up the leg in a barrel. the red line is the water pickup, the red line is the exhaust. the Green is the exhaust relief ports, that you should get a mist or droplets out of. this is your tale tell that the impeller is pumping.

Click to expand...

good illastration tashasdaddy!i of course knew mine had to go in the lake or a barrel and was pretty sure a 25 would have to also of older vintage.

 

tashasdaddy

Honorary Moderator Emeritus

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Nov 11, 2005

Messages

51,019

• Jul 18, 2009

• #8

Re: Shredded impeller

good picture to work with. thanks i kept it on file, for future reference.

buy the way nice boat it is mounted on.

 

6

69 johnson man

Recruit

Joined

Aug 18, 2009

Messages

2

• Aug 19, 2009

• #9

Re: Shredded impeller

I use muffs on my 1969 Johnson 33 all the time. The water inlet to the pump on my motor is a rectangular area of screen just above the sabilizer fin and water comes out the back with the exhaust where the green lines are on your pic. I just have to make sure that the muffs are pushed down as far as they will go against the fin and be sure the hose connection is in the same side as the inlet (inlet is only on one side) of the lower unit.

 

Tim Frank

Vice Admiral

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Jul 29, 2008

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5,333

• Aug 19, 2009

• #10

Re: Shredded impeller

InvaderScott said:

I then lubed the impeller with vaseline, and reinstalled. I figured that a wee bit of rubber safe lube wouldnt hurt a thing.

Click to expand...

Who told you that Vaseline is a "rubber-safe lube"?
It's very much not!