Expert: Brad Sears - 1/9/2012

Question
QUESTION: 56 Belair, 8Cyl 2 barrel, 210 - When it shuts off, stalls or I shut it down, I have to wait about 4 minutes before it will start again. Cranks easily, new starter, voltage reg. I thought it might be a hot coil, so I just replaced that, but still the same problem. Carb has been rebuilt, but I still have a fueling issue. Not sure where to go next.

Thanx, Ted

ANSWER: Sounds like it might be the carburetor but please explain "fueling issue". It might all be tied together. Those Rochester two barrels would percolate, boil the fuel in the carb, on hot shut down and cause a similar problem. But let me know the fueling issue and then we will go from there.

---------- FOLLOW-UP ----------

QUESTION: Fueling issue. Would not start ... no gas coming through jets. I had the carb rebuilt, now starts. Still need to feather the throttel or it will shut down. If I rev it up, it shuts off was the revs come down. I've adjusted the screw, but to no avail. I drove it for about 6 miles the other day, seemed OK, then it started to run rough, like it was starving. When I would give it gas around 45 mph, it didn't want to go faster, then it died at a stop sign. Would not restart. Let it sit for about 4 minutes and it started right up. Replaced the coil, but it still does the same. It has a new battery, starter, voltage reg and ignition switch. Am I better off to get a new carb? This is a single barrel, not a 2 barrel.

Ted

Answer
My little company here in Florida rebuild carburetor, starter and generators. Not an assembly line rebuild but each carburetor is worked on and tested by one person. I have had a number of carburetors that were supposedly rebuilt in the shop and almost to a one there was still dirt in the passages and jets and the linkage misadjusted. e get carburetors sent to us from all over the world. I am eighty and cut my teeth in the auto business overhauling these carburetor when these cars were just used cars. Now your problem souls like carburetor, fuel pump,or tons of dirt in the fuel. I would start by taking a pressure and volume test of the fuel pump. The pressure should be between 4 and 6 pounds. If it is low replace the pump. The pump should also deliver a pint of fuel with the engine idling in 20 to 30 seconds. To make these tests you will need a fuel pressure gauge, not one for fuel injection but one that is also a vacuum gauge. Install a Tee at the carburetor fuel inlet. Rig the open fitting with a short length of copper tubing so that you can attach the hose from the vacuum gauge and the gauge. Take the pressure reading with the engine idling.If the pressure is ok then shut the engine down and disconnect the hose from the gauge and use a peanut butter plastic jar hold the hose in the jar. Have some one start the engine being ready to shut it off on command. The peanut butter jar should be full in less than 20 seconds. If not, the fuel pump is suspect. A pump can have good pressure and not pass the volume test and visa versa. If the volumes fails it could be either a pin hole leak in the fuel line, a plugged fuel line or junk in the tank as well as the fuel pump. Once the fuel delivery system is up to snuff then attack the carburetor. Let me know how you are making out or if you need help with any of the steps.