new impeller keyway is to narrow.

Joined
Jul 23, 2012
Messages
12
I know this is a weird specific request, but can anybody measure the width of the key on their outboard? The engine in questin is a 1963 40hp model# 40353d. its only about a 1/32 of an inch difference so using calipers would be ideal

The key is slightly wider than the notch on the new impeller, and the new impeller is so tight on the drive shaft that I can only slide it about an inch before it gets stuck. My first guess is that I have the wrong impeller, but it looks the same as the one I took out, except the keyway, and the part number on the bag it came in is right (according to the diagram at marineengine.com). I'm hoping this is just a bad part but maybe I have some frankenstein engine beast thing here.

Thanks again iboats... you rock
 

kodibass

Master Chief Petty Officer
Joined
Apr 10, 2010
Messages
864
Re: new impeller keyway is to narrow.

So are you able to get the impeller down to where the flat is ? sounds like maybe you need to give the drive shaft a light sanding and good cleaning, then a light coat of lube. If the key does not fit I would check/re-check that you have the correct replacement impeller. If it is correct I would just file it down a little at a time until it fits.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Re: new impeller keyway is to narrow.

There is only one impeller that is "close". Anything else would be way off. So if yours is close to being right, I'd say you have a bad one.......OR the shaft is buggered up. But that wouldn't explain the key slot.
 
Joined
Jul 23, 2012
Messages
12
Re: new impeller keyway is to narrow.

I think I will order a new impeller to see if it fits better and file/sand this one while I wait.

I noticed the grommet that the water tube slides into (on the engine side) is crushed. Do I need to remove anything to replace this? or does it slide into place from the outside?
 

Watermann

Starmada Splash of the Year 2014
Joined
Jan 12, 2013
Messages
13,747
Re: new impeller keyway is to narrow.

You can just pull that water tube grommet out and push a new one in. I've never seen an impeller that is so tight that it binds on the drive shaft like your saying and combine that with the key slot, I would have say it's the wrong impeller.
 
Joined
Jul 23, 2012
Messages
12
Re: new impeller keyway is to narrow.

Thanks watermann, I'm hoping your right, I just placed an order on marineengine.com and will have to wait and see how the new one fits.

Here are some pics that compare the two impellers
IMAG0281.jpgimpeller.jpg
 
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