I have a Johnson F4B-9 cooling pump which is leaking water from the rear where the cam comes out. I do have a spares kit which includes five gaskets, (one of which I just found in my tea), a rubber O ring which looks as though it is the face plate seal, an impeller and what looks like a grub screw but it is quite long.

I'm a little bit trepidant about taking the bugger to pieces as I have just put my motor back in and don't want any hiccups to slow down the process.

Can anyone tell me if the leak is likely to be coming from the bearing?