Posted by David Sherman on Sunday, October 14, 2007 at 19:47:24 :
In Reply to: No vacuum at all at intake manifold under the carburator. Wh posted by Jesse on Sunday, October 14, 2007 at 19:42:20 :
Clogged up hole between the manifold and where the hose goes on? I don't think a hole that big could be wide open and have the engine still run. On my 67 Chevy pickup, there's a 1/2" pipe plug in the intake manifold below the carburetor. I don't know what it's for, but it once unscrewed itself and fell out. It happened to fall out while I was parked at a rest area (very strange). When I went to start the truck, it wouldn't start unless I gave it full choke, in which case it revved up like crazy even though the throttle was closed. Makes sense because all that extra gas due to the choke was mixing with the air coming through that 3/4" hole so it was almost like a wide-open throttle. Found the hole, and then the plug laying on the ground, put it back in and all was well. It was still a very strange thing to have happen. Anyway, I suspect that the PCV connection is clogged somewhere. Pull the vacuum advance hose or some other vacuum hose, and I'll be you have vacuum there.