Goodyear Sea Bee '51-'53 water pump question

[Jay Apple]

Hey all. I just purchased a Goodyear Sea Bee 5hp, with Model #025-3569 (5D10G) and Serial #509710. I believe it's a '51-'53, and it has only the neutral shift, and does not have the full gear shift. It starts and seems to run well, but the previous owner told me there may be a water pump issue, since no water seems to come out of the upper water output slots. I have the owners manual, and was able to order a replacement impeller (#375688), but given the age was not able to find a complete water pump kit. I figured that the only step I could take is to take it apart, clean it and reassemble with a new impeller, hoping that fixes things.
I have no directions on how to disassemble things to access the water pump. On this model do I need to first remove the power head, or can I simply undo the four bolts on the lower unit and drop it down without messing everything up? Do I need to first drain any oil? Do I need to first order various gaskets to replace when I reassemble? Any guidance you all could provide would be very much appreciated. Thank you in advance!

 

[F_R]

Do Not remove the powerhead

Yes, drain the oil or you will dump it on your shoes later
Disconnect the clutch cable at the lever.
Remove the four bolts and drop the gearcase down and away (this is where you would dump the oil on your shoes.) Pull the clutch off the shaft if it stayed there.
Remove the plate that is above the gearcase. The cable will come down with it. Don't worry, it feeds back up through a tube. Warning--if the top end of the cable is frayed do not pull it down. Check back for further instructions.
The water pump is on the upper side of that plate.

You probably will need a new gasket on top of the gearcase and the one below the pump/bearing housing.

 

[Jay Apple]

F_R, thank you so much for your help. I'll give it a shot.