[drepep]

Hi all,

Well, your advice in my initial carburetor issue (http://www.allfordmustangs.com/forum...ml#post1719616) was spot-on, and I was able to change out the accelerator pump diaphragm with no problem. However, I am still having an issue with getting the car started.

Here are the symptoms (and this is going to be in non-technical "lay speak", so I apologize in advance): when I try to start the car, the engine cranks several times (no battery issue), but the engine never actually "catches". Now, if I pour a wee bit of gas directly into the carburetor, then it starts fine and runs until it stalls. However, once it stalls, I can't get the engine to start again (just keeps turning over), until I get out and do the "gas-in-the-carburetor" trick again. It'll run fine once I get it started, but I don't think that's the way I need to get it done.

I am pretty sure that the issue is in the way the carburetor is set up (hence the post title), but I don't know what to do in order to get it tuned right. Suggestions? Am I looking in the wrong place?

And if you need more information, please ask away! I don't know what to tell you in order to troubleshoot it properly, so I thought I'd jot down the symptoms and see if they resonated with anyone.

Cheers,
Derrick

[macguyver198]

Sounds like you have a fuel pump issue. Either that, or a clog between tank and carb. Easiest check is to disconnect fuel line at carb. Bump starter to determine if you have flow. If you have flow, then needle is not allowing bowl to fill. Adjust float. Could be it got off if you removed top of carb. when you replaced accelerator pump.

[drepep]

Thanks for the quick reply! I just replaced the fuel pump (which is how I found out that the accelerator pump diaphragm was leaking). It truly was bad, but the new one I installed seems to work fine. So, what else should I try as part of the diagnosis?

Again, thanks for all your help and guidance!

[drepep]

Hi all,

I'm still working on getting the Mustang carburetor to work correctly. I have finally gone ahead and opened the top of the carburetor so I could check the float; since the car is on a slant (see "Mustang on driveway (sloped).gif" photo), I would expect the gas to be somewhat lower on one side of the bowl (which it is), but it looks low to me (see "Top view of carburetor (open).gif" and "Another view of float.gif" photos). However, when I manually pump the accelerator arm from within the engine (right side of carburetor), I don't see any gas coming from either of the brass-looking tubes (venturis?) in either barrel (see "Disconnected.gif" photo).

Since the accelerator diaphragm was just replaced, does it look like the issue is one of adjustment (something's not set right), or that there is something more fundamental that I need to do (like rebuild the carburetor or get a new one)? I know this is probably something simple, but carburetors are a mystery to me.

Also, while I was at it, I noticed that there's a hose nipple on the carburetor that has nothing attached to it (see "Disconnected.gif" photo). What does this connect to, and is it a bad thing to have it disconnected?

Thanks for all of your help!

Cheers,
Derrick

[Boomyal]

Yes, you should see gas, thru the annular discharge boosters above the venturis, when you actuate the accelerator pump lever. Something might be plugged up there or your one way valve gummy might be rotted. This little 'plug', in the sidewall of the floatbowl, inside of the accelerator diaphragm cavity keeps the gas from being pumped right back into the float bowl when the pump is actuated. Or you might just need a boil out, although those carbs will take a lot of neglect. Mine has had gas in it for at least 12 years and it still starts and runs like a top.

As for the 'disconnected' port, that attaches to a rubber tube which in turn attaches to a metal line that goes down the right side of the engine and bolts to the bottom of the exhaust manifold directly underneath where the asbestos covered choke heat tube attaches. Even I would like to know exactly what it's purpose is. It is obviously intended to deliver some heat from the manifold up and into the area above the carb opening. It is unregulated so I do not know it's exact purpose. Both the 2100 and 4100 have it.