Well, yeah! I did kinda enjoy it! Moreover, I have no idea what condition the other gearcase is in. Yes, it pushed the boat around this summer, but I don't know what's going on inside. The guy I got it from put in a new impeller & new gear oil, but the actual condition of the gears & seals is unknown to me.
The gauge: Made it myself....yes.
First, I found this. Scroll down & find part 33T.... http://www.stevensinstrument.com/FillPts.htm
Next, I went to the hardware store, looking to find a shrader valve. What I found was a a pressure tester for a furnace expansion tank....hollow metal body with a 1/4" NPT shrader valve & a 1/4" NPT 15 psi gauge in it. Score!!
I took the pressure tester apart, got a 1/4" NPT "close" nipple, and a 1/4" "tee"....then put this all together. All in, I think I spent under $20.