Alpha One Gen 2 water pump impeller

[GHBART]

1992 Alpha One Gen 2 replacing water pump impeller. The OD of the shaft is .875 and the ID of the new (Sierra) impeller is .890. It is therefore a very loose and wobbly fit. I have an old impeller from my 115 HP Tower Of Power and it has an ID of .875.
Something seems not good. Any comments from experience. Thanks

 

[Grub54891]

You got a mispackeged impeller,or a wrong part number.

 

[GHBART]

I bought another impeller from my dealer. I thought it would be Mercury but it was a 18-3056 Sierra. It is also .890" ID the same as the one that came in the kit. Does anyone know why the ID would be .015" (1/64") larger than the shaft. The impeller is very loose and wobbly on the shaft. It doesn't look right but two sources are the same or Sierra is making them all wrong.

 

[Bt Doctur]

just measured a merc impeller and sierra and a driveshaft. the readings are the same as yours. there is play but I would not describe it as "very loose"