Weber anti-percolation revisited

[1QuickS]

This is my third iteration of "anti-percolation" resolutions for Weber carbs (Zeniths also suffer this issue). Classic solution to fuel boiling is to install insulators beneath intake manifolds and drill the top covers ala "PMO" solution which was originated by Ferrari for their 512BBs. I then revised the top cover drilling with my own that spilled fuel into the throats without passing over the idle air bleeds for the idle circuit. The PMO solution spilled fuel into the throats but enriched the idle circuit causing difficult hot restarts. Both top cover solutions spill fuel into the cylinders which can flood the cylinders and cause fire or at least difficult starting. Another issue with the PMO solution that was resolved by second iteration was the idle circuit would be flooded during road race turns (only outer bank of cylinders unless it was a series of esses).

Third iteration takes advantage of un-tapped ports in the top covers. I tapped these ports and plugged the vent tube holes. Into the tapped ports I plumbed some banjo fittings (old Solex 40PI banjos) and now all fuel is discharged to a location away from exhaust headers, cylinders and idle circuit jetting. Venting the float bowls would be through the discharge line.

First picture shows the banjo fittings and breather line ready for installation. Both carbs would have their breather lines connected with a tee fitting and one line would then pass through forward sheet metal to allow routing of discharge line forward of the heat exchangers.

Second photo shows interior of top cover of Weber with un-utilized ports in ceiling of top cover located opposite from the fuel inlets..