40 Deluxe ford

[fordfixer]

Was asked to help a older Lady get her 40 ford running. I usually work on model A’s. It will start and idle just fine it will not accelerate. It starts to make a slurping noise in the carb and wants to die or backfire. Apparently she has had this problem for awhile she has had the carb rebuilt, the generator rebuilt and the dizzy rebuilt before I started looking into it. Was wondering if it could be a vacuum problem.
Any ideas or suggestion will of help.
Thanks

[deuce_roadster]

How long ago was the carb rebuilt, how long did it sit? I would check that first. If it is full of junk maybe the tank needs to be replaced or boiled out and the hard line blown clear and the fuel pump checked as it might have a diaphragm that alcohol gas could eat up. Same for the flex fuel line from the hard line to the pump, those can look fine on the outside and be completely closed off on the inside if old and not rated for alcohol gas.
Depending on who rebuilt the distributor, it should be fine if done by someone who is familiar with those "diving helmet" distributors.
I would eliminate the fuel system first, then check to see if the distributor is correctly rebuilt. Do the plugs get nice blue sparks? Have it put on a Sun or other machine.
This is assuming we are talking about stock parts.

[fordfixer]

I’ve put a known running carb on it. Same scenario. Also put on new fuel pump. Works fine. Dizzy was done by man who has the machine to do the job right. It has fresh gas. I took carb apart and it’s like new inside. Accelerater pump is working.

[drolston]

Check for a nice blue spark that will jump 3/8" at idle, for each plug. Get it idling some dark night with the garage lights off and look under the hood for sparking along the ignition cables. Worn/cracked/soggy ignition cables may allow cross firing and backfiring. Too big of a spark plug gap will aggravate that problem. Set all at 0.025" Check that the spark advance adjustment on the distributor is near centered.

[Ggmac]

Check gas cap , must be vented , stick a vacuum gauge on it and watch while running , should be steady 18-20 in . Watch when dies . Could be blocked exhaust .

[Terry,OH]

Sponsored Links (Register now to hide all advertisements)

The old flex fuel line to the fuel pump can react inside and block fuel flow. Daytona has the best rebuild kits for the 94 Carb. disassemble the top of the Carb. and check if the float bowl will hold fuel without draining. Many times the valves will stick open or slowly close when the engine sits for a long time. MMO usually corrects this as well as driving. I too suggest connecting a vacuum gauge to the engine, at the intake manifold rear vacuum port that typically is used for the wiper motor.

[Als48]

It could be as simple as a timing issue, especially if it has a later 8BA distributor, which could be easily manipulated. You might also take a look at the plug wires. I had a tractor that once had a corroded wire end. It would idle but not rev up. Very hard to start.

Al Hook

[troubadour85]

I'd likely look into the carb just because of the sitting and unknown rebuilder/old gas corrosion. Ignition parts rarely deteriorate over time at least not as fast as a barb. it counds like it could be a float/pressure issue or transition issue with the fuel IMO

[fordfixer]

I checked the vacuum at the wiper port and have 15 inches of vacuum. The engine still bogs down on acceleration. Also will backfire thru the carb. If I choke the hell out of it, it will start pick speed. But the engine is laboring to run.

[fordfixer]

I also found when I had the dizzy checked out, that the vacuum line going into it did not have a Farrell on the line. It just slides thru the fixing.

[Ggmac]

Originally Posted by fordfixer

I checked the vacuum at the wiper port and have 15 inches of vacuum. The engine still bogs down on acceleration. Also will backfire thru the carb. If I choke the hell out of it, it will start pick speed. But the engine is laboring to run.

Is it steady at idle ? Thats kinda low , check timing . Have you checked for blocked exhaust ? Is your gas cap vented ? Both are easy checks

[JayChicago]

Originally Posted by fordfixer

I also found when I had the dizzy checked out, that the vacuum line going into it did not have a Farrell on the line. It just slides thru the fixing.

That fitting does not use a farrell. That fitting has a tapered end that I guess is supposed to be compressed as it tightens, acting as its own farrell.

[fordfixer]

Yes it’s steady at idle, I’ve loosened the gas cap. No I’ve have not checked for blocked exhaust. But it runs like a sewing machine at idle. So wouldn’t a blocked exhaust also affect that? Is there a way to manually advance the timing? I’m used to the model A’s where I can play with it.

[BobR35]

You could attempt to rev it up at the carb and choke it while doing so and see if it continues to rev up. If so, then you know that the problem is fuel related and go from there. If so, I would start with the closest thing, fuel pump, and making sure it is pumping/drawing fuel. Then move on from there to the supply. Keep us posted....good luck

[Ggmac]

Originally Posted by fordfixer

Yes it’s steady at idle, I’ve loosened the gas cap. No I’ve have not checked for blocked exhaust. But it runs like a sewing machine at idle. So wouldn’t a blocked exhaust also affect that? Is there a way to manually advance the timing? I’m used to the model A’s where I can play with it.

A blockage isn’t usually complete, so it’ll allow the motor to run at idle and will gradually interfere with running as the exhaust velocity ( engine rpm ) increases .
It can sometimes make a funny noise as the exhaust gases squeeze by the restriction.
Good luck .
Ps , does yourcar have a driver side exhaust heat baffle ? I dont think it should but with all that could have been switched out in its lifetime its a possibility.

[Terry,OH]

Have you adjusted the two Carb idle air/fuel mixture adjustment screws? Adj. for the highest and smoothest idle, you can watch the vacuum gauge should climb up to nearly 20

[fordfixer]

Well we finally got the lady running again like it should. Found a couple things not right. First the dizzy was not adjust right. Second was the carb. We loosened the gas cap just to make sure. Blew the gas line back to the tank. No problem there. Checked fuel pump for flow. I didn’t want to dig into someone else’s work. Meaning the carb, because she had some one rebuild it. But I decided to take the top halve off to see how much fuel we had. 1/8 th inch. So I bent the tab on the float so the bowl was about half full. It then ran much better. But would only run about half throttle. Played around with it some more, but decided to replace it with a known good running carb for the second time. It now runs just like it should. Just an update to say thanks for all your suggestions.

[hotrodA]

Oops, late to,the party.
FWIW, I had a similar problem with my 40. The previous owner had used a homemade fuel line with an inverted flare end going to the pump, when it should have been a compression ferrule to match the fitting’s seat. . Sucked air on the intake side of the fuel pump. Finally found it, trimmed the flare off, slid on a ferrule and it ran great until the engine blew.