Why am I replacing woodruff key???????

crazy charlie

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Joined
May 22, 2003
Messages
5,493
2000 200hp Saltwaterseries OX66 2 stroke. GREAT MOTOR!!! did 2 water pump services since I got it a few years ago. Extremely difficult to remove woodruff key during water pump servicing. Extremely difficult to replace new woodruff key .Had to sand new key to make it fit this spring.WHY dont I just leave the old key in place?????? Why am I replacing it????? seems like a Pia that I can do without if no harm done.?????? Charlie
 

mike_i

Ensign
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Jun 28, 2017
Messages
939
They are a PITA to replace. I've replaced my water pump several times without replacing the woodruff key.
2000 200hp Saltwaterseries OX66 2 stroke. GREAT MOTOR!!! did 2 water pump services since I got it a few years ago. Extremely difficult to remove woodruff key during water pump servicing. Extremely difficult to replace new woodruff key .Had to sand new key to make it fit this spring.WHY dont I just leave the old key in place?????? Why am I replacing it????? seems like a Pia that I can do without if no harm done.?????? Charlie
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,039
2000 200hp Saltwaterseries OX66 2 stroke. GREAT MOTOR!!! did 2 water pump services since I got it a few years ago. Extremely difficult to remove woodruff key during water pump servicing. Extremely difficult to replace new woodruff key .Had to sand new key to make it fit this spring.WHY dont I just leave the old key in place?????? Why am I replacing it????? seems like a Pia that I can do without if no harm done.?????? Charlie
Guessing

The key is intentionally softer than the shaft to absorb the impact should anything bind up the impeller. Typically a low carbon steel.

The drive shaft is typically a 4xx series stainless. The impeller typically has a bronze hub so you have a dissimilar metals situation.

With the key being less noble than the other materials, it’s the first to corrode.

If corrosion starts down in the key way, it’s never coming out
 
Joined
Mar 1, 2005
Messages
956
The issue of course is that if it corrodes and then snaps, you're really going to have a problem removing the part of the key that is sitting in the depression on the shaft.

I just replaced the water pump on my DF90 last week. The key fell out as soon as I pulled up on the impeller. It really shouldn't get stuck in there.
 

crazy charlie

Vice Admiral
Joined
May 22, 2003
Messages
5,493
The issue of course is that if it corrodes and then snaps, you're really going to have a problem removing the part of the key that is sitting in the depression on the shaft.

I just replaced the water pump on my DF90 last week. The key fell out as soon as I pulled up on the impeller. It really shouldn't get stuck in there.
Mine are loose also.
woodruff keys in this application are supposed to be tough to apply and tougher to remove. If yours "fell out" it either was incorrect woodruff key or not installed properly.
 
Joined
Mar 1, 2005
Messages
956
woodruff keys in this application are supposed to be tough to apply and tougher to remove. If yours "fell out" it either was incorrect woodruff key or not installed properly.
How do you not install a key properly? I can 100% guarantee that the key was specified for my motor.
 
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