Flathead Running rich

[bmwillia]

I have been fighting an issue with my engine running rich.

Some background info:

I am running a Stromberg 97 Carb rebuilt by Max. I have a mechanical fuel pump with a sediment bowl. It is a new pump but I used the spring out of an older pump to get the pressure down to around 2lbs. I have checked the float and it seems to be good.

I have a strong exhaust smell like an engine that runs rich. When I rev the engine I get what sounds like back fires on deceleration out of the tailpipes. Other than that, the engine ran pretty good until about 100 miles ago when it started missing and lurching a little while driving at lower RPMs. I had to put about 5 gallons of 10% Ethanol in it to get home from a trip and I attributed the missing and lurching to that gas, but I have ran two tanks of 100% gas since then and the problem has gotten progressively worse.

Yesterday I pulled the plugs and found they were all black and crusty some worse than others. These are new plugs with just over 1000 miles on them.




I am going to get new plugs but I am not sure where to go from there. Any ideas would be appreciated.

[flatjack9]

Could be ignition related. Misfiring would account for black plugs.

[tubman]

A "Max rebuilt" carburetor? That brings an old saying to mind, "90% of carburetor problems are ignition related while most ignition problems are caused by a faulty fuel system".

Are you sure your coil, condenser, and points are good?

Jack types faster than me.

[Charlie ny]

#2 and #3 are probably correct, however if the power valve at the bottom of the
acc pump well leaks ( who knows why...it happens ) you will run rich. Max will be here
momentarily.
Charlie

[bmwillia]

I have converted the car to 12v and it is a new coil. I am using the helmet distributor and points that were fresh when I started driving the car. I am using a 12v adapter plate on top of the distributor. It and the condenser are new.

I'm not saying those things are not the problem just giving you all the info.

What is the best way to check the condenser and coil?

What do I need to look for with the points?

[drolston]

Sponsored Links (Register now to hide all advertisements)

I recently learned the hard way that when condensers go bad they don't just cause burned points. They can cause missing and lurching and fouled plugs. I also went down the carburetor rabbit hole. Had a little problem mounting it because of size, but the Tubman condenser cured the problem. Seems like every other condenser is a crap shoot. Check out this thread (page 2) to see if some of it applies to you.

https://www.fordbarn.com/forum/showt...light=drolston

[cas3]

When you switched to 12 volts, did you install a ballast resistor?

[bmwillia]

I did not but I bought a conversion kit from Vintage Auto Garage and it is a 3 ohm coil with internal resistor.

[Tinker]

Just a thought or a "wild" idea. How did you check you carb settings? what kind of engine vacuum readings are you getting.


It could be completely electrical.

[flatjack9]

Condensors are easy to replace.

[Veeder]

When you get a chance pull a plug wire and crank the engine you should see a really strong spark if not pull the distributor.

That is another thing to check also the distributor has two sets of points if for some reason they are not set correctly the dwell period will be all meshed up. Remember the points overlap each other to proved the necessary dwell period.

[jimvette59]

The carburetor is loading up. You mentioned you needed to purchase gas.

[Bored&Stroked]

Yes the plug looks bad . . . but it isn't necessarily the carb. Unless the power-valve is leaking, I'd suspect you have other issues - most likely ignition related.

[bmwillia]

I think I am going to start with ignition. This project has taken me several years and many things have changed over that time.

Thinking back to when I ran the engine on 6V I don't seem to remember it running rich or back firing. I'm going to start with ignition and go from there.

First is a new condenser along with new plugs. I have already reached out to Tubman for one of his. I may check my local NAPA for one as well while I'm waiting on Tubman's to come in.

Any recommended brands, or any to stay away from?

[drolston]

Originally Posted by bmwillia

I think I am going to start with ignition. This project has taken me several years and many things have changed over that time.

Thinking back to when I ran the engine on 6V I don't seem to remember it running rich or back firing. I'm going to start with ignition and go from there.

First is a new condenser along with new plugs. I have already reached out to Tubman for one of his. I may check my local NAPA for one as well while I'm waiting on Tubman's to come in.

Any recommended brands, or any to stay away from?

It was a new condenser from MAC's that caused me grief. I am sure many of them are okay, but I would not take that chance.

What kind of spark plug wires are you running. If carbon core or spiral wound, they are prone to connection failure at the ends.

[Charlie ny]

For what it is worth I use a NAPA IH 200 condenser.

Charlie ny

[flatjack9]

I also have used the NAPA condenser.

[tubman]

Mine's purdier.

[bmwillia]

I am really not sure what spark plug wires I'm using but there appears to be a single copper core in surrounded by a white insulator.

[Charlie ny]

In ref to post # 18.....I use Tubmans big brass condensers for most Mallory
and hot rod applications. The IH 200 however is easily adapted to stock front mounted
distributors and has little eye appeal. Tubman's baby is way cool.
Charlie ny

[bmwillia]

Thanks for all of the input. One of Tubman's condensers is on the way. I won't be able to do much with the car till maybe Sunday or some time next week. I'll keep y'all updated as things progress.

Brad

[Ken Henry]

In my experience, plugs like that have always been due to too much fuel. I didn't think a misfire on the proper air fuel ratio would cause plugs like that but could be wrong there?? I would check the float, needle valve, and power valve while waiting for your ignition parts

[scicala]

If a plug doesn't fire one time, then on the next compression stroke there is still a little residual fuel in the cylinder the next time a fuel/air charge comes in. In that case, black plugs make sense to me.

Sal

[bmwillia]

This may be a dumb question, but would a vacuum leak cause a similar issue to what I am having?

[drolston]

Originally Posted by bmwillia

This may be a dumb question, but would a vacuum leak cause a similar issue to what I am having?

Lurching is not typical of a vacuum leak. Vacuum leak will generally manifest as poor idle with little effect from idle adjustment screws, and running rough at higher rpm, but not the lurching. Lurching is usually ignition, possibly carburetor.

[john in illinois]

Sponsored Links (Register now to hide all advertisements)

What air filter are you using. The small hot rod ones do not flow enough and can choke the carb.

John

[bmwillia]

I am running one of the smaller air filters. I'll try taking it off and see how it runs.

[solidaxle]

I had this problem with the small air cleaners. You need to change the plugs also. Removing the air cleaners without clean plugs may not improve anything.

[bmwillia]

New plugs and condenser installed.

removed the air filter and when I did that, I would hear steady pops/back fires out of the tail pipe during idle. That issue went away with the air filter installed.

here is a video https://youtu.be/tExmaCIlNdg - you can hear the occasional popping.

Here is a video from the Engine side, revving it up and if you listen, you can hear the backfiring out of the tailpipes in the back ground after I let off the accelerator. This is what happens on the road when shifting between gears. I took it for a short drive right after this video, and it performed much better than it has been but I did get the occasional back fire out of the pipes between gear while shifting. Not nearly as much as it used to.

https://www.youtube.com/watch?v=YFUjZCBjjYs

I'll pull the plugs this afternoon and have a look at them to see what they look like after that short run.

Brad

[bmwillia]

Pulled #4 plug and its wet and black

[flatjack9]

Not firing.

[drolston]

First, the small hot rod air cleaner (if the filter element is clean) does not choke the engine until the rpm is way up. It is not going to cause the engine to run rich for normal driving.

Second, did the lurching (intermittent momentary total engine not firing) go away with the new condenser and plugs? If so, great - that makes trouble shooting the remaining problem much simpler.

If the only remaining problem the exhaust popping, something is causing some unburned fuel/air to enter the exhaust stream. Main jets too large can cause that to happen, and it will be most pronounced when decelerating in second gear. Since you get popping at idle when the idle circuits determine the mixture, not the main jets, I would rule out the main jets for now.

Having hopefully fixed the ignition problem, maybe you need to adjust the idle jets. Close one until you hear the rpm drop a little, then open it back about a quarter turn. Then do the other. Reset the throttle idle adjust screw to get a nice idle (about 600 rpm or a little less), then do the idle jet adjustments again.

If you are still getting exhaust popping at idle, run some MMO through the carb while jazzing the throttle. If that does not fix it, run a compression test on all cylinders and report back.

[drolston]

My previous post went up before I saw the black #4. Were all the rest okay?

First check that you are getting a strong blue spark at that plug to jump about 1/2". If not run down the ignition problem. Bad spark plug wire; distributor cap crack or carbon trail.

If spark is good at #4 do the MMO and compression test things.

[bmwillia]

The lurching did go away with the new plugs and condenser.

I still feel a bit of a miss when I put my foot in it at times, almost imperceptible, but there. Cruising at about 45-50 in 3rd feels great.

I haven't had time to pull the rest of the plugs. Hopefully will get to that tonight. I imagine they are all the same since they were all black before. Some worse than others, but all of them were real black.

[BobR35]

Originally Posted by bmwillia

The lurching did go away with the new plugs and condenser.

I still feel a bit of a miss when I put my foot in it at times, almost imperceptible, but there. Cruising at about 45-50 in 3rd feels great.

I haven't had time to pull the rest of the plugs. Hopefully will get to that tonight. I imagine they are all the same since they were all black before. Some worse than others, but all of them were real black.

Hey Brad, I just popped on and saw your post. I have been through this same nightmare since I purchased my '35 in Dec. After doing everything several times over, my problem was all carburetor. I even rebuilt the carb but the carb was worn out and it still was running rich and also leaking fuel after turning off. I decided to purchase an aftermarket carb for $150 on ebay to try lastly before spending the big bucks for a new one and since, the car never ran so goooood! Went form 10 mpg to 15mpg. Just my input. Good luck !

[bmwillia]

Thanks Bob!

I'm also getting about 10mpg although I don't think my carb is leaking after turning off.

Since I have not run through all the normal steps, I guess I need to before jumping to a new carb. Hopefully I can get it ironed out before getting to that point.

Brad

[bmwillia]

Update.

Had a little time today so I pulled the plugs and while they were not all black, all had a little bit of liquid on them.

Went ahead and got the engine warm in the driveway and tried to adjust the idle screws. With the air filter on I screwed the first screw all the way in and nothing changed. Then screwed the second in and nothing changed. Backed them out 1/4 turn. Removed the air filter and tried again. The idle did drop a little and it seemed like it was struggling just a little but not much. The popping never completely went away, but it was mess often and less pronounced. Took a drive down the road and I am still getting gargling/popping on deceleration between 1st and 2nd and between 2nd and 3rd.

Also checked the spark on 4 and it was a good strong spark jumping 1/2 inch. (BTW: Make sure the handle insulation on your pliers is good before handling live plug wires.)

Here are picks of the other 7 plugs to go with #4 above.










Sent from my iPhone using Tapatalk

[Ken Henry]

Turning the idle screws in should stall it. It must be getting fuel from another source: blown power valve, dripping nozzle bars come to mind...

[flatjack9]

Looks like a carb rebuild is in order.

[tubman]

As mentioned in the first post, the carb is a "Max rebuild". I assume he means "Uncle Max" who is the best around. I am curious that we have not heard from him. Perhaps there is something funny going on here.

[bmwillia]

It was Uncle Max.

[Terry,OH]

Several guys have suggested connecting a vacuum gauge. Have you done it? Just disconnect the wiper vacuum line and connect vacuum gauge to the engine there. Should be a steady reading of close to 20 at idle.

[Shoovel]

Check out Charlie Price from Vintage Speed on YouTube. He has several videos on rebuilding carbs. He also has all the pieces you may need for your carb.
Good luck.

[tubman]

"Uncle Max" or Charlie Price? I know who I'd back in that contest.

[bmwillia]

I plan on checking vacuum but I am also finishing up a bathroom remodel so I have not had much time to work on the car much.

"Uncle Max" has been great in email communication in the past, though I have not emailed him recently.

The car has been running rich since day 1, but I didn't realize how bad it was until the lurching started and I checked the plugs. Keep in mind, I am a newbie when it comes to cars and engines. I have learned a lot but still have a lot to learn.

I went back through some emails with Max last night from November and he mentioned fuel pressure as a possible culprit.

I do have an after market mechanical pump but I put the spring from my old pump in it to lower the pressure. I checked it back in November and thought it was good, but as I said, I am new to this so its possible I was mistaken.

If y'all think fuel pressure could be the problem, I'll try to check it out this weekend.

I have thought about just buying a regulator from speedway to make sure the pressure is correct.

Brad

[Ken Henry]

Sponsored Links (Register now to hide all advertisements)

The problem with too much fuel pressure is that it overwhelms the needle valve that regulates the fuel level in the carburetor bowl. The fuel level gets too high and overflows down the throat of the carburetor which you should be able to directly observe by peeking down into the bores. So, while it is good to know what the pressure is, it is not really needed in order to know whether it's causing a problem - the excess fuel can be observed directly.

[Terry,OH]

Uncle Max also sells Stromberg parts. He works for Stromberg and is their technician. He does like to use the input fuel valve that use two balls to shut off the fuel to the float bowl. These valves can sometimes hang up due to dirt in the fuel. Do you have a fuel filter? How about a photo of the engine bay. showing the fuel pump.

[Bored&Stroked]

How did you check your fuel pressure? The fact that you can turn the idle mixture screws all the way in and it continues to run means that excess fuel is being dumped into the engine . . . and about the only place is from the carb. Your plugs look really washed down - which means raw fuel.

Note: If you've been having issue like this for awhile, make sure you change your oil - it probably has a lot of gas in it.

Do you have a quality in-line fuel pressure gauge - after the fuel pump? You may need a fuel pressure regulator . . . and don't buy those cheap chrome looking ones with the dial on top - buy a Holley low pressure regulator and make sure you have a liquid filled pressure gauge AFTER it. You want the pressure to be 1.5 to 2.0 lbs MAX.

[bmwillia]

I'll try to get a picture of the engine bay up soon. I am running a glass bowl fuel pump. The bowl was clean last I checked.

I checked the fuel pressure inline between the fuel pump and carb with a vacuum/pressure gauge. It was back in November I think so I don't remember exactly what it was reading, but I want to say between 2.0 and 2.5 lbs.

[Ken Henry]

Do be afraid to look in there while its running. The pops you are hearing could correlate with drips of gasoline coming off the nozzle bars (there should be no drips)

[BigGameJames]

Originally Posted by Charlie ny

#2 and #3 are probably correct, however if the power valve at the bottom of the
acc pump well leaks ( who knows why...it happens ) you will run rich. Max will be here
momentarily.
Charlie

Hate to highjack the thread but Charlie how can I get one of your distributors for 1953 ford flathead v8 (eab heads) to run dual 94 carbs?
Since I am new, they won’t let me send PM’s.
Any help would be appreciated.
Let me know.

Thank you.

[tubman]

Just post a few relevant comments and "hello's" and you'll soon have the required 10 posts. That rule is necessary to weed out the scammers that prey on the folks in the "Swap Meet".

[BigGameJames]

Thank you.

I do appreciate.

[40cpe]

Originally Posted by BigGameJames

Hate to highjack the thread but Charlie how can I get one of your distributors for 1953 ford flathead v8 (eab heads) to run dual 94 carbs?
Since I am new, they won’t let me send PM’s.
Any help would be appreciated.
Let me know.

Thank you.

Charlie Schwendler <[email protected]>

[Tinker]

Originally Posted by Terry,OH

Several guys have suggested connecting a vacuum gauge. Have you done it? Just disconnect the wiper vacuum line and connect vacuum gauge to the engine there. Should be a steady reading of close to 20 at idle.

A vacuum gauge would also rule out sticky valves also (lurching). The vacuum gauge will tell you a lot about a motor and how you should setup the air/fuel mixure screws on your carb. It's just an old-school engine diagnostic tool and you don't have to plug in your laptop to use it.

If you screwed in both air/fuel idle screws and it did nothing (should have stalled the motor). I'd venture to say you have a vacuum leak. It maybe carb, but it's hard to say without a check.


two things you should do on any motor you own. A compression check and a vacuum check.

[bmwillia]

Thanks Tinker.

Anyone have any idea what the thread size/type might be for the wiper port on my intake manifold? The only thing I can find to fit it is the original nut for the wiper tube which I filled with some solder to close off and use as a plug.

My plans for this weekend are to look for signs of too much fuel pressure and test vacuum(if I can find a fitting for the wiper port) and compression and report back.

[Charlie ny]

For what it is worth....from my experience too much pressure will in short order flood
fuel out of the carb, that is only my opinion. From a distance I do believe you have
an internal fuel leak, possibly a faulty power valve. Unless the ignition is actually
letting you down.
Charlie ny

[jimvette59]

Get the carburetor rebuilt. No mater who did the carburetor before any part can fail. JMHO.

[bmwillia]

I was able to get a little time in the shop yesterday. Fuel pressure is definitely one issue. Running just over 3lbs. I've ordered a fuel pressure regulator from Jegs.

The carb may need to be rebuilt, but I don't think I've eliminated all of the other possibilities yet.

[Tinker]

Under 4lbs on a strom97 should be fine. But yes it could be a collection of things.

[bmwillia]

Took a vacuum measurement. The gauge says its in the "Late Timing" range. How do I fix that?

Here is a video:

https://youtu.be/XcotyoNPuxI

Thanks!

[petehoovie]

[Terry,OH]

Your engine seems to have a lot of valve lifter noise. IMO I would have Charlie Schwindler check out the fuel pump and get the pressure down and not install a pressure regulator. NAPA sells fuel filters for the glass bowl pump. Ask Charlie to install one. Remove the Carb input valve and clean. Then see if the Carb idle adj screws work and adjust the engine vacuum to the highest and most steady reading. Make sure you change the engine oil. A photo of the engine bay would be nice. You don't seem to have a vacuum leak which would result in a lean fuel mixture. You could remove the Carb top and see how much dirt is in the float bowl. If having the fuel pressure and the Carb input valve clean does not allow the idle mixture screws to adjust correctly then return the Carb to Max after calling him.

[bmwillia]

Thanks for the advice Terry! I really appreciate it!

[Tinker]

Another vacuum chart attached. When you get down to fine tuning best to do one change at a time then regroup. When you get there. New motor to you, it can be a lot of different things compounded. Understand why is important.

Vacuum is low, but that could be as described above.... What kind of cylinder compression are you getting. Keep at it!!!


I believe Charlie is a bit backlogged due to personal life issues. But I believe he also works on 97s. If you are sending him your fuel pump, maybe 2 birds as they say.

[bmwillia]

Sponsored Links (Register now to hide all advertisements)

Is it better to check compression with the engine warm or does it matter?


Sent from my iPhone using Tapatalk

[Phil Gillespie]

[QUOTE=bmwillia;2014090]Is it better to check compression with the engine warm or does it matter?

Normally checked when warm, ie around running temp. Then if low a bit of oil down the bore and a rechecked to rule out rings perhaps.
Phil NZ

[bmwillia]

Update:

I sent my fuel pump and carb off to Charlie and have received it back. He found a few issues with the carb and lowered the pump pressure from a little over 3lbs to 2.5lbs.

I have not had a chance to try them out yet because why they were away, I did a compression test on each cylinder and got a consistent 80lbs on every cylinder but #8, it was at 30lbs.

I pulled the intake and head on that side and it appears that the intake valve is not closing all the way. There was some carbon build up around the valve seat from it running rich. I have cleaned it and the valve is still not fully seating. Any ideas?




Sent from my iPhone using Tapatalk

[bmwillia]

Hey guys, I wanted to post a quick update on the running rich issues I have been chasing down.

I believe my issue is resolved. Here is what I have done since my last post.

I changed the bent exhaust valve on cylinder #8 and put everything back together with my fuel pump at 2.5 lbs and the issues Charlie found with my carb straightened out.

I was still having backfiring issues on deceleration between gears so I turned my attention to the ignition system. All of the plug wires checked out good so I pulled the distributor and sent it off to Skip to have him go through it. Got it back last week and installed it this morning. My car has never run better!!! No more backfiring on deceleration and plenty of power while driving.

The car used to bog down when I floored the accelerator in 1st gear, now I have good power all the way though all of my gears.

A big thank you to all of you who helped me through this problem!!

[AKCJ]

Great to hear you’re running well. It’s gotta be a good feeling.