The Ford Barn

old ugly · 10-31-2021, 11:35 AM

Quote:

Originally Posted by Big hammer

Bingo !! Your first test, dribbles with the gas line valve open, you should have a good flow like when you drained the carb bowl ! Remove a gas line fitting after the gas valve and blow compressed air back into the tank, you'll hear junk pop back into the gas tank!

i think he is saying that "with the bottom carb drain off its only a dribble"

so if you have good flow at the line into the carb but not at the carb drain then it most likely that the problem is inside the carb.

Gene F · 10-31-2021, 11:52 AM

Points too close.

nkaminar · 10-31-2021, 03:19 PM

If you get good flow with the bottom of the carburetor off but dribbles when the drain removed then it is likely that the float is hanging up. Take the carburetor off and shake it up and down and turn it over to check to see if the float moves freely. If not then take it apart to see if you can figure out where it is hanging up.

nkaminar · 10-31-2021, 04:11 PM

Deleted

noboD · 10-31-2021, 06:40 PM

You said you used brake clean to check for vacuum leak and it slowed down? I don't think brake clean burns. Better try something else, maybe propane.

1crosscut · 10-31-2021, 06:57 PM

Sponsored Links (Register now to hide all advertisements)

I'm not a big fan of the modern points. For me they are more difficult to set the point gap.
Your say your points gap isn't adjustable. You should be able to adjust it. What is the measurement of the gap you have now?

Pull the fuel line off at the carburetor and test the flow at that point. While you have it pulled free from the carburetor look to see how much of the fuel line sticks out past the ferrule. If it sticks out too far it can push against the fuel filter screen in the carburetor causing a lack of flow.

When you sprayed around the manifolds the engine speed didn't go up but went down. Just the fact that it changed speed when you did so it points to a leak in that area.

Leave the condenser in place when running the car. Swap it out for a new / different one instead.

You got to go for a test drive or two before March to make sure it's fixed!!

Brad in Germany · 10-31-2021, 07:20 PM

I had a similar problem where my engine started and idled just fine, but when I revved the engine to higher RPM's, it sounded like it was choking (starving for fuel?) and if I kept the accelerator pressed down, the engine eventually started to back fire (quite loudly).

I tried all of the things mentioned above with no success.

It turned out that my spark plugs were fouled (and possibly shorting at high RPM's). Once I thoroughly cleaned them and especially cleaned (and lightly sanded) the electrodes and then re-gapped them.....everything now runs perfectly.

Brad in Maryland

old ugly · 10-31-2021, 08:43 PM

the problem with the modern points is. good quality points are hard to find. most of them now have a plastic follower instead of the bakelite type. the plastic follower is rivet to the point spring and will cause a point of high resistance which will melt the plastic follower which will close up the point gap. i have changed so many of these junk points that now i will never put in a modern points plate. the original style point work just fine.

look at the points follower and see if it is plastic and if it is still intact, if they have melted and tightened up the point gap up throw them away and see if you can locate a good set that have the hard follower or change back to the original style points.

super flat · 11-01-2021, 03:22 PM

If your rpm changed with brake cleaner you have a vacuum leak!

noboD · 11-01-2021, 05:49 PM

Quote:

Originally Posted by super flat

If your rpm changed with brake cleaner you have a vacuum leak!

Zactly. He said the idle went down when he sprayed brake clean. BC does not burn so it would go down not up.

bavArian · 11-02-2021, 06:33 AM

Quote:

Originally Posted by noboD

Zactly. He said the idle went down when he sprayed brake clean. BC does not burn so it would go down not up.

I know that there's a small leak at the throttle shaft, but I'm still not sure if the manifold has a leak to the block because some of the bc-spray gets sucked in by the carb as well.

Guess I'll have to check again with a short hose connected to the carb to make sure. Why it should only occur at higher rpms/load is something that's beyond me though, I doubt the manifolds heat up so fast that a crack would open up.

Anyway, first on the list is flow testing the jets and changing the float valve.

1crosscut · 11-02-2021, 06:38 PM

What is the measurement of the points gap?

dpson · 11-03-2021, 07:59 AM

Beg, borrow or steal (ok, don't steal one) a known good running carburetor and put on your car and see what happens.

MichaelSchwarzer · 11-04-2021, 01:33 AM

Hi, where are you located? I have some flow tested working carburetors here. We could do some road tests next spring.
Cheers Michael

bavArian · 11-04-2021, 06:26 AM

Quote:

Originally Posted by MichaelSchwarzer

Hi, where are you located? I have some flow tested working carburetors here. We could do some road tests next spring.
Cheers Michael

Hi Michael,

thanks for the offer, I've sent you a pm.

To everyone else, I'll report back after checking the jets.

Greetings,

Daniel

bavArian · 03-19-2022, 10:52 AM

Update:

Last week I ordered a new float valve for the carb and installed it. The first test drive today was promising: It can now run up to around 45 mph without stalling and doesn't stall even when climbing a hill with ~10% with mid rpms in 2nd gear. (~15-20 mph)

I did notice however that the ignition advance lever didn't make a lot of difference. It is working, as I can feel the engine start to knock when I advance while idling, but there's not much difference on the road whether it's on 10 o'clock or fully pulled down.
So I'll check the timing tomorrow, maybe it's a bit retarded.

The torque at low rpms is good as it pulls away from a standstill nicely. As soon as I reach said 40 to 45 mph it just stops accelerating and starts to sputter, I think through the muffler, from time to time.

Also when running the carb dry to park (at ~1000 rpm I'd guess) the engine runs normal but just before it dies the revs climb noticably for maybe 1 second.

Am I right that it's still running too rich on at least the main jet and possibly also the others? GAV was completely closed by the way.
Haven't flow tested the jets yet, that's next on the to-do-list after an oil change.

bavArian · 04-29-2022, 10:01 AM

Another update:

In the meantime I disassembled the carburettor and flow tested the jets. Main and cap jet were relatively fine, with the main being a bit too lean. (fixed that, now they have the proper flow)
The comp jet flow was way too high, around tripple the normal flow rate. Soldered it up and tinkered with it until the flow was right.

Now the car won't go past 35 mph, it seems to run too lean. (getting lots of vibrations at ~30 - 35 mph without any backfire, no smoke as far as I could see)

MichaelSchwarzer sent me one of his spare carbs for testing and the engines runs fine with that one. Top speed was ~55 mph (measured via gps) and it pulls nicely as well.

That means it's definitely a carb-problem.

I've noticed there are 2 differences between Michaels carb and mine:

- the shaft of my throttle plate has a bit of play on the lever-side
- turning the GAV on his car seems to make a difference compared to the one on my carb

So I'll have to re-check the GAV on my carb, it seems to me that either the secondary well doesn't get enough fuel from the float bowl or the GAV won't allow enough fuel to pass to the cap jet.

Is that the right direction or am I totally wrong?

Thanks and have a nice day,

Daniel

BillCNC · 04-29-2022, 01:21 PM

This just happened to me, ... in the end, it was the Armored Ingnition Cable shorting out when ever the vibrations got to much. Drove fine under 35 mph, or under 1300 rpm.

Regards
Bill

Gator6 · 07-02-2022, 06:26 AM

Quote:

Originally Posted by bavArian

I know that there's a small leak at the throttle shaft, but I'm still not sure if the manifold has a leak to the block because some of the bc-spray gets sucked in by the carb as well.

Guess I'll have to check again with a short hose connected to the carb to make sure. Why it should only occur at higher rpms/load is something that's beyond me though, I doubt the manifolds heat up so fast that a crack would open up.

Anyway, first on the list is flow testing the jets and changing the float valve.

Daniel, I am having the same exact problem. I just bought my car about 6 months ago and haven't driven it much because I broke everything down, dropped the pan, drained the radiator, replaced the water pump, new battery, all new tires, etc etc. So While I was at it, I decided to rebuild the carb. Everything came apart fine and went back fine, but now when I drive at high RPMs, no power and it starts to backfire. So I'm going to replace the condenser, and then start on the carb. How exactly do you flow test the jets? Is there a link anyone can share?

Thanks. Newbie Rich

CT Jack · 07-02-2022, 07:06 AM

Please explain what you mean when you say you have a split fuel. I have one line exiting my fuel tank that feeds directly into the carburetor.
Do you have access to a Zenith carburetor that is known to be working properly? I would remove your existing carburetor and try running with the Zenith. It appears the carburetor you have been using has some internal flow problems at the higher flow operating range. As someone has mentioned you are starving for fuel at the higher engine speed range.

10-31-2021, 11:52 AM	#22
Gene F Senior Member Join Date: Mar 2012 Location: Ohio Posts: 1,958	Re: Engine sputters and dies when at high rpms and under load Points too close.

10-31-2021, 03:19 PM	#23
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,899	Re: Engine sputters and dies when at high rpms and under load If you get good flow with the bottom of the carburetor off but dribbles when the drain removed then it is likely that the float is hanging up. Take the carburetor off and shake it up and down and turn it over to check to see if the float moves freely. If not then take it apart to see if you can figure out where it is hanging up. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

10-31-2021, 04:11 PM	#24
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,899	Re: Engine sputters and dies when at high rpms and under load Deleted __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

10-31-2021, 06:40 PM	#25
noboD Senior Member Join Date: May 2010 Posts: 319	Re: Engine sputters and dies when at high rpms and under load You said you used brake clean to check for vacuum leak and it slowed down? I don't think brake clean burns. Better try something else, maybe propane.

10-31-2021, 06:57 PM	#26
1crosscut Senior Member Join Date: Feb 2011 Location: Lincoln, Nebraska Posts: 1,907	Re: Engine sputters and dies when at high rpms and under load Sponsored Links (Register now to hide all advertisements) I'm not a big fan of the modern points. For me they are more difficult to set the point gap. Your say your points gap isn't adjustable. You should be able to adjust it. What is the measurement of the gap you have now? Pull the fuel line off at the carburetor and test the flow at that point. While you have it pulled free from the carburetor look to see how much of the fuel line sticks out past the ferrule. If it sticks out too far it can push against the fuel filter screen in the carburetor causing a lack of flow. When you sprayed around the manifolds the engine speed didn't go up but went down. Just the fact that it changed speed when you did so it points to a leak in that area. Leave the condenser in place when running the car. Swap it out for a new / different one instead. You got to go for a test drive or two before March to make sure it's fixed!! __________________ Dave / Lincoln Nebraska

10-31-2021, 07:20 PM	#27
Brad in Germany Senior Member Join Date: May 2010 Location: Potomac, Maryland Posts: 911	Re: Engine sputters and dies when at high rpms and under load I had a similar problem where my engine started and idled just fine, but when I revved the engine to higher RPM's, it sounded like it was choking (starving for fuel?) and if I kept the accelerator pressed down, the engine eventually started to back fire (quite loudly). I tried all of the things mentioned above with no success. It turned out that my spark plugs were fouled (and possibly shorting at high RPM's). Once I thoroughly cleaned them and especially cleaned (and lightly sanded) the electrodes and then re-gapped them.....everything now runs perfectly. Brad in Maryland

10-31-2021, 08:43 PM	#28
old ugly Senior Member Join Date: Aug 2021 Location: alberta canada Posts: 585	Re: Engine sputters and dies when at high rpms and under load the problem with the modern points is. good quality points are hard to find. most of them now have a plastic follower instead of the bakelite type. the plastic follower is rivet to the point spring and will cause a point of high resistance which will melt the plastic follower which will close up the point gap. i have changed so many of these junk points that now i will never put in a modern points plate. the original style point work just fine. look at the points follower and see if it is plastic and if it is still intact, if they have melted and tightened up the point gap up throw them away and see if you can locate a good set that have the hard follower or change back to the original style points. __________________ old ugly my old father-in-law told me. "listen close when people tell you how to do stuff they may know something. then do it the way you want."

11-01-2021, 03:22 PM	#29
super flat Senior Member Join Date: Jan 2011 Location: west bend wi Posts: 314	Re: Engine sputters and dies when at high rpms and under load If your rpm changed with brake cleaner you have a vacuum leak! __________________ I am usually relatively happy------Gary

11-02-2021, 06:38 PM	#32
1crosscut Senior Member Join Date: Feb 2011 Location: Lincoln, Nebraska Posts: 1,907	Re: Engine sputters and dies when at high rpms and under load What is the measurement of the points gap? __________________ Dave / Lincoln Nebraska

11-03-2021, 07:59 AM	#33
dpson Senior Member Join Date: Apr 2014 Location: Montpelier, VT Posts: 223	Re: Engine sputters and dies when at high rpms and under load Beg, borrow or steal (ok, don't steal one) a known good running carburetor and put on your car and see what happens.

11-04-2021, 01:33 AM	#34
MichaelSchwarzer Member Join Date: Apr 2013 Location: Germany, Europe Posts: 42	Re: Engine sputters and dies when at high rpms and under load Hi, where are you located? I have some flow tested working carburetors here. We could do some road tests next spring. Cheers Michael __________________ www.fordmodela.com

03-19-2022, 10:52 AM	#36
bavArian Senior Member Join Date: Sep 2019 Location: Germany Posts: 215	Re: Engine sputters and dies when at high rpms and under load Update: Last week I ordered a new float valve for the carb and installed it. The first test drive today was promising: It can now run up to around 45 mph without stalling and doesn't stall even when climbing a hill with ~10% with mid rpms in 2nd gear. (~15-20 mph) I did notice however that the ignition advance lever didn't make a lot of difference. It is working, as I can feel the engine start to knock when I advance while idling, but there's not much difference on the road whether it's on 10 o'clock or fully pulled down. So I'll check the timing tomorrow, maybe it's a bit retarded. The torque at low rpms is good as it pulls away from a standstill nicely. As soon as I reach said 40 to 45 mph it just stops accelerating and starts to sputter, I think through the muffler, from time to time. Also when running the carb dry to park (at ~1000 rpm I'd guess) the engine runs normal but just before it dies the revs climb noticably for maybe 1 second. Am I right that it's still running too rich on at least the main jet and possibly also the others? GAV was completely closed by the way. Haven't flow tested the jets yet, that's next on the to-do-list after an oil change.

04-29-2022, 10:01 AM	#37
bavArian Senior Member Join Date: Sep 2019 Location: Germany Posts: 215	Re: Engine sputters and dies when at high rpms and under load Another update: In the meantime I disassembled the carburettor and flow tested the jets. Main and cap jet were relatively fine, with the main being a bit too lean. (fixed that, now they have the proper flow) The comp jet flow was way too high, around tripple the normal flow rate. Soldered it up and tinkered with it until the flow was right. Now the car won't go past 35 mph, it seems to run too lean. (getting lots of vibrations at ~30 - 35 mph without any backfire, no smoke as far as I could see) MichaelSchwarzer sent me one of his spare carbs for testing and the engines runs fine with that one. Top speed was ~55 mph (measured via gps) and it pulls nicely as well. That means it's definitely a carb-problem. I've noticed there are 2 differences between Michaels carb and mine: - the shaft of my throttle plate has a bit of play on the lever-side - turning the GAV on his car seems to make a difference compared to the one on my carb So I'll have to re-check the GAV on my carb, it seems to me that either the secondary well doesn't get enough fuel from the float bowl or the GAV won't allow enough fuel to pass to the cap jet. Is that the right direction or am I totally wrong? Thanks and have a nice day, Daniel

04-29-2022, 01:21 PM	#38
BillCNC Senior Member Join Date: Aug 2017 Location: SoCal Desert Posts: 826	Re: Engine sputters and dies when at high rpms and under load This just happened to me, ... in the end, it was the Armored Ingnition Cable shorting out when ever the vibrations got to much. Drove fine under 35 mph, or under 1300 rpm. Regards Bill

07-02-2022, 07:06 AM	#40
CT Jack Senior Member Join Date: May 2010 Location: Hebron, CT Posts: 432	Re: Engine sputters and dies when at high rpms and under load Please explain what you mean when you say you have a split fuel. I have one line exiting my fuel tank that feeds directly into the carburetor. Do you have access to a Zenith carburetor that is known to be working properly? I would remove your existing carburetor and try running with the Zenith. It appears the carburetor you have been using has some internal flow problems at the higher flow operating range. As someone has mentioned you are starving for fuel at the higher engine speed range.