Going over my fuel system, other than the engine shutoff t handle, I can't find an inline shutoff switch. I'm used to gas engines where they're turned off at the end of every run. Should there be one in this system? The manual refers to one, but if it's on or near the tank, that requires panel removing in there aft berth.
Porchhound,
I don't have one on my boat and don't really see the need for one and I guess Catalina didn't see a need either. Getting a new (to you) you're going to have a lot on your plate, don't barrow trouble. In other words if it's not broken don't fix it.
Also since you've now got a boat maybe you need to change your name from Porchhound to Boathound!
I years ago I installed a Racor 500 turbine fuel filter under the head sink to replace the smaller OEM one. I also installed a fuel shutoff valve right above it.
There was a 1/4 turn fuel shutoff valve on the fuel tank. If you look in the locker under the head sink you should be able to see it on the pick up tube. It isn't reachable. I relocated the valve to the top of the door opening.
Porch : On my 1988 C34 there is a butterfly screw-in gate valve cutoff on the top of the fuel tank that is accessible by unscrewing the Beckson port in the floor of the port side cockpit locker. That's a real pain to get to!!
Like Noah I installed a simple ball valve cut off (90 degree turn) in the fuel line just before the Racor filter. Easy to get to!!
A few thoughts