Drilling/modifying impeller bores

[billw]

In the past, I have modified a few modern, readily available impellers to fit an application where the originals were NLA. I have had some success with this, even though my methods have been crude. This is because the impellers I was modifying were not very tall. Now, I would like to drill a hole to enlarge the shaft diameter of a taller (about 7/8″) impeller. I had a used one to experiment with and my hole came out off-center and crooked, even though I used a drill press. Have any of you guys had better luck? If so, how did you do it? Thanks.

Note: In particular, I am going to try to replace an automatic trans. Mercury impeller with one from a 9.9/15 Yamaha. As some of you know, those impellers take a bad set, even when relatively new and become useless in a few years, even if not even run. My idea is to use the Yamaha impeller, which has a better, more pliable and flexible material, and is darn close to the right overall size, except the bore.

Long live American manufacturing!

• This topic was modified 4 years, 7 months ago by billw.

[Tom]

Bill,

If what see on the interweb is right, that’s a six vane impeller. That lends itself really well to chucking in a three jaw lathe chuck. I’ve done a few this way and they have come out fine. Message me on this board, or call me at 508 844 eight two two eight.

Tom

[jcrigan]

I have used a piece of pvc pipe and set the impeller in that. Filling in the spaces between the vanes with plaster will hold everthing in place.

[Buccaneer]

I’ve only done a couple of impeller “re-fits”, and only had to enlarge the
hole .010 or .020 thousands, but an adjustable reamer worked great,
just by holding the impeller by hand.

Prepare to be boarded!

[Author]

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