My Ol' Man did an engine swap in an old farm truck. The motor runs strong, but he is having trouble with the carburetor operating correctly. I am in another state, so I am not sure of all the details, but here is what he described.

It is a '79 two barrel carb and runs pretty well once it warms up a little, but when he steps on the accelerator it dies. He said he can get it to rev up just fine if he holds the choke open with screwdriver. However, as soon as he lets it go it dies or runs rough.

He said he checked all the vaccum lines and cables, as well as disassembled the carb and cleaned it with no help. I thought it might need to adjust the initial choke opening and check the fast idle cam and make sure the choke plate/linkages are not binding.

I know this ain't much to go on, but does anyone else have any suggestions? Any help would be appreciated. Thanks!

I am assuming the engines were the same, if so i would put the old one back on the new engine. Otherwise take the time to get a rebuild kit, these are not to hard or expensive to rebuild and well worth the time. Who knows how much crud, varnish, water and corrosion is inside that carb. Or you could just buy a new carb and toss that one.

Could just be a leaking gasket at the base of the carb. Spray some carb cleaner around the base at idle and see if it smooths out.

if there are no vacuum leaks check to make sure the fuel isn't being restricted somewhere ie filter or bent line.

it wouldn't explain the rough idle but sometimes if it won't rev up it's the excellerator pump. Tell him to check the squirters to make sure they are squirting

I just built one of those for my dump truck and they are really easy to build.

My guess is vacuum leak

The one thing that caught my eye was the screw driver holding the choke plate open.

Does this mean that the choke plate never opens even when warm?

What I would do is convert it over to a manual choke. Just about every carburated vehicle I have ever owned, I did this to because I had such a problem with the electric or those stove pipe things.

If the choke isn't the issue, then I would start looking at vacuum leaks for the idle. Double check the mixture screws and the idle screw and adjust if necessary.

Then if you get the idle to settle down, and it still won't really go then I would consider the accelerator pump and I would start looking there.

And other things I would check as well are timing. If he had the distributer out during the swap, it is possible that it is off a tooth which I have found will cause odd running conditions. I had my Olds do this to me one time where I could get it to idle and seemed to be fine but if I put power behind it, it would pop and die.

The old motor was newer and ran a 4 barrel carb, this is a two barrel.

Great suggestions. I will run these things by him. He did say he set the timing, but it never hurts to go through it again. I also like the idea of the rebuild kit and checking the accelerator pump. I know he had it apart to clean it up, but I don't think he mentioned the rebuild.

Thanks again!