Fuel starvation or leaning out at highway speed

[persiflage]

Picture the scene:
Spring. Sunny Friday afternoon. Time to get MOT, following car/engine rebuild, which had been behaving perfectly on the drive. MOT station was approx. 6 miles away and the route includes about two miles of the type of road the Elan was made for ... at about 4 miles the car started to show distressing signs of a major fuel problem and at about 5 miles ground to a halt. Thankfully in a bus stop pull in. Being before the mobile phone era, I was forced to find a public phone and arrange a tow home
After a little tinkering the car was again running sweetly ... on the drive ... and the weekend was spent trying to figure out the reason.

Monday. MOT attempt #2 ... only to be confronted with exactly the same symptoms, a breakdown at the same bus stop and a phone call to the same pal with the tow rope.

Major investigation and a finger down the fuel pump mounting hole showed the jackshaft lobe had failed and the wear was considerable. Result: sufficient throw on the pump to fill and replenish the carbs at idle and slower speeds but an inability to keep up with the demand of even a little enthusiastic driving!

Sometimes its the simple things that floor us!