Stalling at idle. Did the engine start again easily or did it need a lot of cranking and then bumble and lope to life?
How did the engine run before it quit? Loping, bumbling or any unstable running?
It could be an air leak in the fuel system. These engines will clear small quantities of air although they will bumble and lope. If the air volume is enough they will quit like all diesels.
Fuel filters clogging should also show a loss of power or a slowdown as they clog.
Go over the filters and be sure they are not clogged or leaking air into the system.
Check the tank vents as sometimes they can get clogged restricting air to the tank as the engine runs and the fuel level reduces. At some point the vacuum could be enough to stop fuel from reaching the engine. Not so likely here without other signs but is worth being sure.
If it was a very abrupt stall, no warning, like someone just turned off the switch , then may be that is close to what happened.
There is an electric fuel control shutdown/run valve on the PT pump, in the vee, which needs power to run. Check that the wire is tight and the connection is in good condition.
That valve could also be failing , the coil failing or the fuel seals inside the control valve, NOT the PT pump, which could allow air or just shutdown.
The ignition switch could also be faulty. On mine, the ign. sw. RUN position operates a small relay which provides power to the coil along with the guages. If that ign sw. OR that relay dies or the wiring they control is poor then the fuel valve could lose power resulting in a shutdown like the ign. sw. was turned off.
Check it all, all the wiring for loose or corroded connections.
Intermittent problems like this can be a pain.
If the engine ran well before the quits then it may just take some time to I.D. the cause.
