I have tried all sort of things to keep the heat off my 48IDA. The carbs usually stay cool during driving, but rapidly absorb heat when the engine is stopped. After a while the fuel inside the acceleration pump circuit start boiling and pours fuel into the throats, making starting difficult and washing my cylinders off
oil.
The phenolic spacers did help some, but still are not the solution, besides that the air horns are too close to the bonnet and I have experienced the horns being knocked off its position by the rocking engine.
So I have decided to go a different route. Since I have a mechanical fuel pump and want to stay that way, I have purchased a solenoid valve, 12 Volt, normally open, with Viton seals, which I am going to plumb between the fuel pump and the pressure regulator.
One simple push switch in the dash and a relay behind it will do the trick.
Before turning off the engine, maybe 5 seconds before (I have to test the time it takes for the bowls to become empty), I push the switch which activates a relay, wired to hold itself activated until the ignition is turned off.
So the fuel supply is interrupted for a while, the fuel level inside the bowl and the acceleration pump circuit will sink and when the engine is turned off fuel will be low enough to prevent it from boiling over into the throats when the carbs get hot with engine heat.
I will take the phenolic spacers off and hope to get done with the fuel issue.