It's been quite a while since I wrote anything about the Saga, so here we go.

You may remember, many years ago, I wrote about an anti run on system I dreamed up, wherein I applied manifold vacuum to the overflow ports on the carbs. Well that worked, briefly, before the running on started again. A useless system, after all, so I ripped it out. Over the years I have been considering why it didn't work, and concluded that the vacuum applied sucked fuel or vapour, directly into the inlet.

I still felt that the principle was sound, just needed a better source of vacuum, that didn't mind some fuel or vapour. I considered the cruise control vacuum chamber, but was unhappy about the thought of getting fuel in there. To find out how much vacuum is needed I had the engine running and, with a length of hose, sucked on the overflow ports, almost instant killing of the engine, with barely any suck, so not much vacuum needed. Now what sources of vacuum do I have? Manifold - tried that but didn't work, cruise control, not happy about fuel in there. What about the PCV system? It has a slight vacuum via either the carb PCV ports or the mushroom valve, and will briefly maintain this vacuum, in the crankcase. The system would also be self purging, once the engine is running again. Interesting idea, so how to control it? When I initially scrounged the solenoid valve for my first attempt, I actually got two valves, one an ON OFF valve and the other, unused, one, a changeover valve. I contemplated using this changeover valve, to apply vacuum, when the engine is turned off, but leave the ports open to atmosphere otherwise. Next I considered all sorts of weird ways to turn the valve on when the engine was turned off, but eventually came up with the solution, invert the function of the valve, so when the engine is turned off the valve is also off, but switched the the overflow ports to vacuum. Turn the ignition on, the valve turns on also and connects these ports to atmosphere, for normal breathing. Turn the ignition off and the valve is also turned off, switching the ports back to the PCV vacuum.

Built it with all the bits and pieces I had, in my junk box, and voila the engine just stops. Brilliant, now will it continue to work or die after a short while? I've now done several trips, both long and short and only once was there a single firing of the engine before it stopped. Otherwise a nice smooth shutdown, none of the trying to jump out of the engine bay, tricks.

Bits used, a T piece and elbow and bits of rubber vacuum hose.

Now to wait for the wreckers to open after New Year, to scrounge another solenoid valve, to duplicate this, in Wooly Wolseley.