Hot engine - gas in carb percolates
05-10-2014, 01:18 PM
#1
Hot engine - gas in carb percolates
As the title states, when I shut off the engine the gas in the carb percolates and discharges into the intake manifold and onto the top in the intake on the driver's side. I removed the carb and installed a rebuild kit, but the problem remains. I've had similar problems on my big block Mopars, and I solved the problem with thicker intake gaskets or phenolic insulator plates. Does anyone know where I can get a thicker carb mounting gasket (like 1/4") for an original '64 Carter carb? I'm hoping that might help the problem.
05-10-2014, 02:44 PM
#2
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05-10-2014, 02:45 PM
#3
As the title states, when I shut off the engine the gas in the carb percolates and discharges into the intake manifold and onto the top in the intake on the driver's side. I removed the carb and installed a rebuild kit, but the problem remains. I've had similar problems on my big block Mopars, and I solved the problem with thicker intake gaskets or phenolic insulator plates. Does anyone know where I can get a thicker carb mounting gasket (like 1/4") for an original '64 Carter carb? I'm hoping that might help the problem.
Also, have you blocked the hot slot in the intake manifold directly under the carburetor? Next, try wiring the heat riser open as this will keep the plenum much cooler so you may get less heat soak after shut down. Finally, is the vacuum advance working properly, this should give the engine at idle and cruise approx 15* extra timing and this will keep the engine much cooler.
Last edited by tbarb; 05-10-2014 at 05:28 PM.
05-10-2014, 05:24 PM
#4
Thanks for the info. Our car has an AFB carb with a gasket, stainless shield, gasket combination... no phenolic shield. I'll check the parts suppliers to see where I can buy one. I have not blocked off the heat cross over passage in the manifold, but that was an option that I was going to try if all else failed. The engine is cold blooded when first started, so the extra heat in the manifold is helpful then. The heat riser operates freely, and I haven't wired it in the open position, but that was another option that I had considered.
05-10-2014, 05:36 PM
#5
Thanks for the info. Our car has an AFB carb with a gasket, stainless shield, gasket combination... no phenolic shield. I'll check the parts suppliers to see where I can buy one. I have not blocked off the heat cross over passage in the manifold, but that was an option that I was going to try if all else failed. The engine is cold blooded when first started, so the extra heat in the manifold is helpful then. The heat riser operates freely, and I haven't wired it in the open position, but that was another option that I had considered.
I would install the correct gasket,phenolic spacer and shield and get some small freeze plugs and tap them in the hot slot and block that passage. Go for a ride and see how much improvement after good and hot. You may not need to wire the heat riser but it makes a big difference in the temperature of the plenum so keep this in mind.
If the engine is cold natured go through the choke adjustments in the service manual. The correct setting for the choke coil is a approx 68* set it to where it just fully closes the choke blade.