Thank you both for the replies.

I'm confident it isn't the drain plugs. I tried snugging the housing bolts. The two upper bolts took 1/8-1/4 turn but I didn't want to over torque them so I didn't strong arm it. I ran it for a few minutes and, if anything, the leak is worse now. I can't see exactly where it is coming from because it is coming from underneath and the mounting foot is in the way. It does seem to be coming from around the seal plate.

If it was the shaft seal would the water be coming from the motor housing itself rather than from around the seal plate?

---

I feel stupid for thinking that different motors could affect the shaft seal. The shaft would have to be a particular size for a given pump model regardless of motor. Still, better to look foolish than run into problems once the thing is apart

On the pump model the problem is that there is no model number on the pump housing. There is only a small stamped plate that says hayward and is otherwise unreadable no matter how I shine light on it or try to take a rubbing of it with a pen and paper. The strainer cover does have sp-1600-D on it and the basket SP-1600-M and it does look like the super pump so I'm assuming it is a 1600 series super pump. Are these two item numbers enough to be able to determine what I need? I looked up the parts list at hayward for the spx 1600 and it suggests 1600 models were made as far back as the early 80s so it looks like this makes sense. Are the SPX and SP parts interchangeable or have there been significant changes made to 1600 models over the years?

When I put the motor back on how tight should I make the 4 screws? I don't have a torque wrench. Should I just hand tighten and then snug them 1/4 turn or should I give it more than that, say 1/2 turn? I have a feeling it is easy to crack the housing or seal plate if one goes crazy with it.