Suspect a plugged pickup screen inside the fuel tank. The clue is that usually it will run okay for 10 - 15 miles before the problem occurs. If that's how it acts, you might be able to remove the hose going into the pump, then blast it with compressed air to blow that sock off the pickup tube. If you have a lot of black smoke from the tail pipe and the engine runs normally when it is cold, suspect a choke that isn't opening. You can wire it open as a test but the fix is to remove the choke's thermostatic spring and the metal dish under it, then chop out the carbon that is blocking the passage. Also check the heat riser valve in the right exhaust manifold for proper operation. It is supposed to close when it's cold so all the exhaust from the right side has to go through the head, under the choke spring and base of the carburetor to warm them, then out the left side. If that passage is plugged, the thermostatic choke spring won't open the choke. Many of the newer intake manifolds on the 318s, 340s, and 360s don't have that removable dish under the thermostatic spring. For those the manifold has to be removed to clean the passage. The clue is the manifold should be very hot by the thermostatic spring within a few minutes of starting the engine.
Monday, March 21st, 2011 AT 12:28 AM