I pulled the intake manifold (only) and put a bead of "Permatex Ultra Copper" around the inlets where they contact the block (exhaust) gasket and also on the intake to exhaust gasket.? Let that set most of the day and then fired it up.? It runs really sweet now.

On my 1933 I had a persistent manifold leak either the intake or the exhaust no matter how many times I tried lining up the two manifolds and installing new gaskets. Finally to the intake/exhaust manifolds, bolted together, and had the mounting faces surfaced. It only cost a few dollars and it really fixed the problem.

OK, so I used my MAPP gas torch to confirm that there is a substantial intake manifold leak.? Lots of folks on other forums said that propane, spray carb cleaner, or MAPP gas could be used to find the leak.? To use the torch I got the engine running (with choke) then first put the tip of the torch into the carb and turned it on enough to hear the engine speed change.? Then I took the torch and moved it around the various joints of the intake manifold.? Sure enough, there were definitely a couple of places where the engine sped up as I passed the torch over.

I've got a mechanic friend coming over tomorrow who is going to look the engine over and advise the best way to get everything sealed up.

Thanks! :)? I've checked around and now believe that the problem is either:

• Intake Manifold Leak
• Plugged Idle Circuit in the carburetor

The first one is more likely.? I'll be checking these items (in order) this weekend and will report back.

The only thing I changed on the carb when removing was the "petcock" (or whatever that knob is) at the bottom near the fuel inlet.? I had to give it a quarter turn to get enough clearance to line up the carb studs.? I put it back when I was done.? I'm pretty confident that item doesn't regulate anytyhing that would cause these symptoms.

Running with the choke closed indicates an overly lean condition.  You might have an air leak between the carb and the manifold, or the intake manifold and the block.  does your manifold have a vacuum access port for windshield wipers or other accessories, is it open or leaking?? Try putting some oil in a squeeze bottle and applying some oil to the intake block gasket interface.  the oil will temporarily block any intake air leaks at that area.  If it smoothes out, you probbly need to retighten your  intake manifold connections.  Remember not to tighten to much(12 to 15 lb ft is the right neighborhood) as the intake/exhaust manifold need to move some during the heat cycles. 

Did you mess with any of the carb settings during your work? Is the linkage back where it was is the idle speed screw set as it was, is the idle mixtur screw set where it was?

Check out troubleshooting section at following site.

http://p15.biz/

I've recently acquired a 1932 PA with the original flat head four engine.? The car has been running and driving but definitely needed some work.? Today I replaced the manifold gasket to fix what had been a bad (and noisy!) exhaust leak.? Once I got everything back together, the car would start (with choke as usual) and now runs much quieter.? However as I ease off the choke, the engine slows way too quickly, sometimes backfiring, and then dies.? I can get it to keep running smoothly at a "fast idle" with the choke out about 1/3 of the way.

I don't think that fixing an exhaust leak would have these kinds of symptoms.? In the process of doing this work it is possible that I bumped an adjustment on either the carburetor or the distributor.? FYI: previously it would run in a slow but somewhat lumpy idle without the choke.? Any guess as to what would cause the motor to "fall off idle" when the choke is turned off?? I'm thinking that this could be a timing problem since I know that timing can impact how a motor runs when lean vs rich.? I don't currently have the right tools or info to accurately test the timing, but that's "on my list"? ;)