Flathead Stalling when comming to a stop

Hello,

My father and I are working on a 1931 Model A Deluxe Coupe with a 48 flathead.

We resently rebuild the carb (Single Ford-Holley 94 Carb) and added a Fuel Pressure Regulator as there is only an electric fuel pump, and that was putting out like 6lbs.

At start up the engine runs and idles fine. We adjusted the fuel pressure regulator to 2.5lbs.

Upon doing a road test everytime we slowed down to a stop, the engine would die. It would start right up and while going through 1st and 2nd would run fine. Every now and thenm while in 3rd (maybe 35-40mps) the engine would sound like its starving for gas and the car would chug. But every single time coming to a stop it dies.


Any Ideas.


If the idle adjustemnts need tweaking, how do I tell when it good enough. Because at idle it sound just fine. Do I make a slight adjustement then test run around the block?

Since I added a Fule Pressure regulator (Set to 2.5 lbs) should I maybe increase that to like 3lbs.


Thanks in advance

 

Increase it to 3 and see what happens. I had an 8BA with electric pump and had regulator set at 4 and it ran fine.

 

You may have to take the carb apart to check your power valve gasket, reset your pressure (2.5 SHOULD be good) and if the problems continue pull the carb.

 

Crank the idle mixture screws out 1/4 turn at a time to see if this helps. Though higher speed miss will be a different problem.

 

Adjust or check your initial timing too before making any carb adjustments.

 

Thanks for the info. Have not had a chance to dso any testing or tweeking just yet


Just a couple of question (please forgive the ignorance)


1) for the Idle mixture screws. The rebuild kit we got had no instructions for setting these screws. Is there a rule of thumb to use. Like turn all the way just before it dies, then back out a 1/4 turn or something to that effect, and do the same for the other screw. or is there somewhere online that can provide exact steps to take for this carb (Single Ford-Holley 94 Carb)


2) If the timing was off at all, would it still idle fine. or at idle it would sound and run rough.

Like I said it idles just fine, when taking off going through 1st and 2nd it sounds fine, just when coming to stop it dies.

 

For initial setting on the idle circuit turn them in all the way and then back them out 1-1/2 turns, then fine tune your idle circuit with a vacuum gauge to reach highest vacuum at idle speed. You will have to jump back and forth a few times to get it dialed in.

 

Is it the physical 'stopping' of fwd movement that causes it to die, or just the letting off throttle? If you get the car rolling, then put it in neutral while idling, and then stomp the brakes does that kill it?

When my 97's did that, re-adjusting the float levels fixed it (were too low).

Also, you didn't buy one of those Mr Gasket dial-type regulators did you? If so, replace it with a good Holley low-pressure unit.

 

^^^^^ what he says ^^^^^