Impeller fab – if you had your druthers

[fifty20ne]

I need on like this 1/2 ” .500 i.d.
I know there is an OMC impeller the has right i.d., height, and drive pin arrangement
You just have to turn O.D. down, ( smaller).

Does anyone know the OMC impeller part #?

Thanks,

Bob

[green-thumbs]

Mercury Part # 47-24447 for vane type impeller
Mercury Part # 47-24427 for oscillator type (formerly M-50-137)

Reason for brass hub in most impeller is because when rubber is molded by vulcanizing process (heat) it does not stick or bond as well to steel as it does to brass or copper. The core for 47-24447 vane type
impeller is a substantial piece of brass with some machining…both of
which make for high costs compared to molded plastic or nylon core.
Steel can be given a copper flash plating to which rubber will bond
however, plastic has replaced metal in many applications due to improved plastics and cost advantages.of injection molding over processes to form metal.

Several points worth noting in photos
1) C spring is a later replacement…had to get a tool at Sears to remove
2) If you open up water pump and find an incomplete impeller, chances
are some of the rest is still somewhere in cooling water system
3) 1940 propeller does not have the cushion in back of hub and is sheer pin drive. 1941 and later models have the recess in back of hub
for rubber cushion and are adapted for either rubber clutch or sheer pin.
4) NOS oscillator had a tag on 47-24427…Mercury Part # Would you
have reached for your wallet as fast as I did? Sellers of parts often
are only interested in moving the merchandise at a profit. It pays to
know what you are looking at.
5) The seal in 3 slit type water pump is a bugger to remove, but, replacement is often way past due. Seal is a stock item 4923

• This reply was modified 4 years, 1 month ago by green-thumbs.
• This reply was modified 4 years, 1 month ago by green-thumbs.
• This reply was modified 4 years, 1 month ago by Mumbles.

[geary]

Kirk,
I was surprised to see that your original impeller was a 5 blade as most of the ones I’ve seen are 6 ? Can you take a picture of the actual pump cavity and show how much offset there is from the prop shaft to the sides of the cavity, also the dimensions i.e. inside diameter, depth and shaft diameter ? Hopefully to show the intake and discharge ports in the pump housing ? Knowing how a flexible impeller pump works as the impeller rotates and creates the positive and negative pressures makes it easier to see if another style impeller will work when installed ! I’m betting a 6 or even 8 blade impeller would work just fine in your engine !

Thanks

Gary

[kirkp]

Gary, I’ll work on pulling together the info you asked for. I don’t have any profound thoughts about the 5 blade design or how long it’s been in there. I would think awhile since all the vanes are worn to a point. Don’t see why a 6 blade wouldn’t work and maybe even a 8 blade. I noticed on the impeller list that’s been floating around that the majority on the list are 6 blade.

Louis, awhile back you posted a pic of a vaned impeller along side a wobbler impeller. (pic below) Was this a 24447 impeller? I printed it off and scaled the dimensions and it worked out to 2.06″. Happen to remember where this impeller was purchased from?

Kirk

[green-thumbs]

Yes, that is an impeller for a 3 slit water pump. I purchased it years ago
from Grubb East Coast Marine. At the time his supplier had decided to
stop making impellers. So it is No Longer Available. Mr Grubb retired not
long after.
As for outside diameter, look at the vane impeller in preceding thread. notice that the vanes take a set which in effect reduces diameter. In this
case I believe “Close enough is good enough”
The STRONG stream of water flowing out to Joe B’ s Wizard WD3 indicates that as long as impeller is reasonably close to original that
the motor is happy. AND MUCH better than worn out or on their last
legs impeller. A friend had the unhappy experience with his Mark 30
impeller that shed its vanes…scored cylinders before he was
aware water pump was kaput.
Louis

For what it is worth, every original impeller I have seen was 5 blade
while replacements all seem to be 6 blade. Perhaps a patent issue.

[Author]

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