With that engine model known, maybe Doug or someone else can help you. Obviously, the model, year, and engine can all render the boats with different equipment. 100 miles from the boat, you should have duplicate copies of the manuals. I have then and I have dups for both- and my boat is only a couple hundre yards away for easy access !
Northeast of N.O.
Same on the 31... there is a round hole under the aft cabin mattress to reach the shutoff valve. Works well when changing the primary filter.
I have a 2004 B323. It has the Yanmar 2GM20F as Ron pointed out There are 2 fuel shutoff point that are controlled by T-handles. One is on the engine instrument panel in the cockpit, The second is beside the battery switches in the entryway to the aft cabin...
Looking for the latter. I’ll check again when I get to the boat later this week. (The skipper that was doing delivery experienced engine trouble, which is why he stopped short. He texted me last night saying he now suspects the fuel pump. So I might try to find diesel mechanic to meet there.)
Mechanical or electric? Mine is mechanical but I’ve put an electric one in line with a switch that I use to bleed the engine after fuel filter changes. Good for a back-up.
On that 331 that I chartered, the previous charterer pulled the fuel shutoff / stop handle in the aft berth, by the battery switches and I didn't notice that the handle remained pulled out in the shutoff position. We motor sailed from Pensacola, FL to Orange Beach, AL and halfway back, the following day, the engine started sputtering and eventually stopped (approximately 6 hours later)! I had been told by the charter company on an earlier date that the shutoff valve didn't work so not to worry. Apparently it did work; however, it took 6 hours of run time before the engine stopped. After pushing the handle back in (run position), the engine picked up the fuel prime and ran fine thereafter. So, Fullbore, make sure that you locate that additional handle and ensure that it is pushed in.