Water pump impeller clearance

Hello all,

Is it normal to have some end play in the water pump impeller shaft?

I was measuring the impeller clearance and was struggling to get a .010" feeler gauge in between the impeller and the housing. The manual states .012" is minimum. If i push on the impeller, I can feel it move, and the feeler gauge fits slightly loose. Do any experienced folks out there think this is normal? I think this play must be the clearance in the impeller shaft gear as it doesn't appear to have a bearing involved and is possibly quite normal.

I also suspect that a feeler gauge isn't very accurate as it is too stiff to conform around the curve of the housing and it is quite possible that a .010" gauge is more like .014" clearance.

I didn't make any changes while it was apart other than replace the gasket and clock one of the elbows. This new to me engine has 2100 hours on it, and I suspect other than the end play it has been running this way for most of its life.