Perhaps if it is no real hassle part of this thread might be best to appear in the maintenance section if thought to have any value..?
Doug/Mogdriver... Many thanks for taking time to reply re the fuel pump control circuitry. I liked the entirely logical idea that the fuel pump might be fed as you suggest via the ignition switched START circuit while the ign key was in the cranking position thus OVER-RIDING the opened contacts of the oil pressure switch to then supply the pump.... At which stage hopefully the carbs will have been fed enough fuel to initially fire up the engine, and once fired up, hopefully enough oil pressure will have been raised during that process to close the oil pressure switch contacts, and thus maintain the supply to fuel pump in order to feed the carbs when the ign key is returned from the START to the RUN position ...?
As you suggest Doug, with the engine now running and the fuel pump in operation, the oil pressure switch can then act as a safety device in the case of an accident, where it is possible that as the result of the circumstances relating to the accident the ign may have been be left ON risking fuel being pumped out of a damaged fuel pipe. In such a situation with the engine stalled as the result of the accident, the oil pressure will have dropped to zero, the oil pressure switch contacts will have opened and thus the electricity supply to the pump will be cut, stopping fuel delivery.. Thus the oil pressure switch can and does act similarly to inertia switch used in other vehicles to cut off fuel in an accident situation....?
However in the case of MY carb fed 1985-6 Morgan it`s fuel pump appears to be directly fed via the oil pressure switch alone, which determines that with no oil pressure the fuel pump has no supply. My old Mog was totally stripped and restored by it`s garage business Morgan enthusiast owner circa 1999 (?) As the result of those works it is ever possible that wiring modifications could have taken place, I believe it is also possible that an anti theft device was fitted during that time, which it seems likely would inhibit both the fuel pump and starter solenoid supplies.
I have doubts that the wiring of the fuel pump was altered other than it`s primary supply during the anti theft device fitment, but not quite in the frame of mind to cut into the harness to prove a point (at this time), however in order to prove to myself that my +8 operated as I suggested, I removed the white with red tracer at the starter motor solenoid, in order to remove starter motor activation out of the scenario while the ign key was turned to the START position, as expected I heard the relay energising to bring the (now disconnected) starter motor solenoid into circuit... HOWEVER, there was no fuel pump ticking, which I take as proof that MY +8`s fuel pump operates as I suggested in my mail...?
It would seem ideal if other carb fed +8 owners could determine the operation of their fuel pump circuitry..?
GoMoG is indeed a world leading source of assistance for Morganeers and others. Sorry I have not seen the info you mention relative to the fuel pump circuitry Doug.
In many circuits there can be ways of TEMPORARILY by-passing safety switching in order to get you home if a switch fails, and it is well worthwhile to know where and how to create a by-pass. HOWEVER leaving such by-passes in place as the result of forgetfulness may create a risk in an accident...?
I suspect that lengthy periods of lay-up, which has come to be the norm for many classic cars, played no part in vehicle design and construction, and given that digitally controlled vehicles with all sorts of bells and whistles seem to have a constant draw on their batteries, many laid up cars suffer from top condition batteries ever going flat in time, add to that scenario less than 100% efficient batteries, likely to loose charge at an even quicker rate, thus lay-up can and does create issues that require careful consideration..