I just discovered that my rough running and low idle seems to be cured when I disconnect the left hand fuel cut off solenoid. The solenoid clicks and is supposed to cut the fuel off when you turn off the ignition, but this one seems to run on negative energy. Weird. How can this be? I've ordered a new one, but I suspect the carb will need a flush out. Anybody else had this? 2 litre 79
Might you have set up the carburettor to just-about idle even though the fuel cut-off solenoid is not actually moving? Then when it does decide to move your idle mixture goes badly wrong? Take the solenoid out and check that the valve plunger is actually moving, reliably, just to be sure?
I wish I could check this, but it's not the valve with the plunger on that you can see but the other one nearer to the back of the bus and that's all sealed up. I've now tried to see what happens when I switch the left and right cut offs. The cut off itself doesn't seem to be the cause as both produce the same effect when screwed into the left hand carb. I've blown some compressed air into the hole, and the effect has seemingly lessened. A more comprehensive strip down is needed I think.
Its probably leaking fuel past the fuel metering needle valves so it runs very rich. Shutting off the idle mixture leans it up ... Does your oil smell of petrol or never need topping up ?
For info I think I've almost corrected it though not entirely sure of the reason. First off though I took the left carb off and cleaned it out. Then noticed when back on that the choke flap wasn't quite going into the vertical position. Once I'd discovered the choke flap I was able to correct this by turning the unit slightly anticlockwise, then balance the carbs more accurately. It now idles better at a higher speed and the fuel cut offs work. Not perfect yet but I do think the right hand throttle stop had got out of adjustment so at idle more of the power was coming out of 1 and 2 cylinders.
