The Stovebolt Site Forums The Shop Area Engine Shop 216 Won't Stay Running

Rebuilt 216, new everything on it, starts initially but stalls if accelerated. When engine is shut down it will not restart. When running it requires full choke, and when the choke is opened it begins to stumble and will stall if not chocked. The timing may be off slightly but what else could be the problem? Please, this engine, which was completely rebuilt, has not run right since installed, any thoughts? Thanks


Dave

Vacuum Leak

What would you say is the most likely location of the vacum leak? The vacum line to the wiper is new and the vacum motor rebuilt, the vacum line on the carb is tight, and the vacum advance is new? Your thoughts? Thanks.

Dave

A leak that large would most likely be at the manifold to head surface. there's a torque sequence to the assembly like the head. Do you have a vacuum gauge? Also I think I remember some rings inside the intake runners that compressed inside the block, but I could be wrong - It may be an old Chrysler I'm remembering.

Anywhere where there is a gasket in the intake system could be suspect. Recheck all the bolts in the intake as well as the carb base. You might also check the line going to the advance, make sure the fittings are tight.

One of the newfangled gadgets we're using on complex vacuum systems now would also be useful if you do have a vacuum leak. It's a "smoke machine" that diagnostic techs are using to pinpoint tiny vacuum system leaks that trigger trouble codes on the computerized jobs. By introducing smoke into the intake under a low positive pressure with the engine off and tracking down any leaks, it's possible to find even very tiny ones. A major leak shows up in a hurry.

Another way to go about finding a leak involves backing off the intake valve adjusters until they're all closed and putting a couple of PSI of air pressure into the carburetor air horn with an air hose and a pressure regulator, then listening for leaks with a piece of rubber fuel line used like a stethoscope. I adapt a piece of radiator hose to the carb top, and bush the other end down to accept a quick-connect for my air line. Low-tech, but it works.
Jerry

What they said.

And, why not check that timing, with the engine off. Do a search for static timing, or just static. There are many posts on this.

Also, is the carb mixture set right?
Does the accel pump work?

If all the above is copacetic, a great trick for finding vacuum leaks that I learned right here at stove bolt, is to use a propane torch. Not lit, and pass it over the intake manifold joints, carb base, etc. Its gotta be a big leak, if the above has been checked, and you are still having the problem. Don't do it inside, and don't get on fire.

A vacuum gauge would be a good diagnostic tool. Cheap, and really works well. Once you are running right, you can re check your timing while the truck is at idle too. I never knew just how useful they were, until I got me a stovebolt.

I had this happen and it ended up some grit in the gas that needed to be wiped out of the carb. The float kept sticking.

Hi, sounds like a lack of fuel in the carb or to the carb. Could be plugged fuel line, bad fuel pump, float level set wrong, plugged main jets in carb, accelerator pump not working. First to check is the fuel pump output by removing the fuel line at the carb and turn the motor over with ign. off. Have someone with a container to catch the fuel. SAFTY NOTE: Do this outside with a fire extinguisher close by. If you are getting fuel to the carb it is a carb problem, if not, check fuel flow from tank to fuel pump, if good,fuel pump bad, if not, fuel outlet in tank plugged or fuel line from tank to fuel pump plugged.

Guys:

Thanks for the info, there is a wealth of knowledge here, and I will tart with the vacum issue first. The fuel pump, line, tank, and filter are all good. The carb is a new rebuilt, but that still could be the problem. Any other thoughts please let me know.

God bless,

Dave

HI, I did forget 1 thing, check that the idle mixture screw is at least 1 1/2 to 2 turns out to start with, then adjust as required when running.