Technical Hemi Engine and Powerfite transmission stalls on idle or take-off

I got an engine stall problem with a 1955 Dodge 270 Hemi 2-barrel engine and the PowerFlite transmission. (1) Whenever I put it in drive either the engine dies or the car herky jerks on take-off. (2) It has a rough idle and slowly dies after about one minute. (3) When I stop an an intersection the engine dies unless I put it into neutral and hold the foot pedal down for fast idle. But on take-off it jerks or sputters. Once I get it running it drives on the highway 55 mph or city streets 35 mph OK ... but when I stop, the engines dies, or when I re-start from a stop it jerks. Mechanic said he timed it but I can't be sure. I had a mechanic try to adjust the idle mixture screws and the fast idle screw and he had no luck. Compression in the cylinders is 95-110 psi and the vacuum is 15-16 Hg. We sprayed the intake manifold with starter fluid to try and find a vacuum leak, but could not find one. I bought new rebuilt carburetor, and new dual points, condenser, distributor cap, spark plugs ... and no change, problem still there. What do I do now? Voice your comments or suggestions please. -- Richard

 

Sounds like you loaded and shot the parts cannon, now you need to diagnose the actual problem. Sound like vacuum was checked, but was it steady (I'll bet not)? It would be real nice if you could find someone with a scope to see if you have any bad plug wires and if the ignition system is operating correctly. If you put your hand over the carb to mildly choke it, does it run better or worse? That would give you an idea if it was rich or lean. Your description sound like you have a miss. Are you sure about the compression test? Did you check every cylinder?

 

Idle circuit, transfer circuit, main circuit. One of them isn’t happy. Have you opened the carb yet?

 

Not being able to adjust the mixture could be due to a few things, but maybe the float is set too high and you’re dribbling fuel in.

 

This. ^^^^^^^^^

 

That was gonna be my guess

 

Check the Vacc advance can on the Dist. Also check the Fuel Pump volume and pressure. So many little things can cause that and just because you bought a rebuilt Carb doesn't mean it's done right. With issues like this on an unknow older running motor first place I go is to check the condition of the Timming Chain!

 

I declare this Basic Diagnostics Week!

 

That's for sure!

 

Well, if we don't scare the new guy off he has a check list of the most 'usual' culprits to sort thru.

 

A forum like the HAMB is a good place to get usable, logical diagnostic advice like checking things such as float level and other carb adjustments, checking fuel pump pressure and volume, checking compression and ignition timing, inspect distributor operation, etc. We can provide plenty of suggestions online, from afar. But we can't say specifically to find a certain screw at a specific location and give it 1/4 turn clockwise to cure your problem.

At some point the OP has to read and learn about how to do this kind of work himself and have the necessary tools at his disposal. Or find someone with the skills and equipment and pay them to do the work. Or find somebody that can show and teach him how to do the job, hands-on.

There may even be a HAMB member that lives near him they would be willing to give him a hand. But until the OP returns and gives us some more information, like his general location, we may never know.

And he should also consider removing his phone number and email address from his original post.

 

What is the base idle speed, warmed after running a while? Then Check plug wires. Dies it miss at idle or just rough? Idle speed is step one, too high and the transfer slots are open making mixture screws ineffective.