Hi guys, I am back with my 76 Spit run on problem.
Took the following actions since I last signed on:
1. Installed the run on valve and did the plumbing as the shop manual shows for the a car with Strombergs carbs, as there is no schematic for one with SUs.
2. Installed an Oil Cooler
3. Tries a couple tanks full of premium gas
The problem is still there, altough the car runs a bit cooler due to the oil cooler installation. Although the Anti Run on valve is wired and plumbed properly, it doesn't appear to have any effect. I don't believe it creates the vacuum in the top of the fuel bowl, to offset gas being drawn through the jets. I did change the plumbing so that the valve would let the air into the manifold to screw up any combustible mixture, but that didn't work as the hose connection on the valve is only 1/4 of an inch, not enough air getting through.
Letting the car idle for a couple of minutes does work. I guess the only option left is to take the head off and clean chambers and piston tops.