Stumbling 8BA went drivable to bad

Hutch07

Hutch07

Junior Member
http://www.youtube.com/watch?v=ELXqNWEpAR4

My 1950 8BA flathead is chugging after it warms up. I have the original 8BA labeled carburetor and glass fuel bowl. After I sit on the side of the road for about 5 min and let it just idle it will let me get enough RPM and feather the clutch to "GET HOME" about 1 mile at a time. It seems like there is a sweetspot in the throttle that I can feather the pedal to get down the road and it will happen again. Once it cools down it starts like a dream and will idle all week.

My first thought is the fuel pump.

This is my first flat head and would appreciate a lesson or two.

The stumble is there when I first start but not as bad. It will idle all day but when it warms up it really chugs and becomes impossible to drive.

I Have tried disconnecting the vacuum advance and driving but there was no change.

Maybe fuel pump??
 
Here are a couple of pics of the carb
 

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sounds like you have plugged fuel system, did you pull the glass bowl off an check it some have filters , did someone put a filter in line maybe under the car, when it chuggs does it smoke black could be fuel pump, need to ck. pressure should be @4-6psi also poss. power vavle in the carb could be leaking causing flooding
 
Do you have any oil in the air cleaner? It is an oil bath and is suppose to have oil to filter out the dust and dirt. If it is empty you aren't getting any filtration..
 
4-6 lbs is too much,should be more like 2-3 #Max. Could be carb or FP. Disconnect line from carb and crank engine with the key off. into acan it should pump out in squirts every second or so then you know pump is ok. and must be carb is at fault. ken ct.
 
Ken is right 2 1/2# of fuel pressure at the carb is all you need, start with a fuel pressure check, then needle and seat, if the needle is rubber tiped get a new needle and seat with the steel tip, check float level, is it to high or two low, will the float float or does it have fuel in it, when it starts acting up look down the carb, do you see fuel leaking down the throat, i have found that letting an engine idle that is doing what yours is the carb is low on fuel, not enough in carb to let engine run at speed, but idling doesnt use much fuel so the carb can slowly fill up and run good again, its a pain but if you can remove the top of carb and see how much fuel is in it, borrow a good carb from a friend and try it, you can eleminate a lot of guessing doing that, alt of things could be wrong, so check all the easy things first, then go to the harder things, my advice for what its worth
 
Thanks a bunch for all the information. I did clean the glass bowl but did not remove the top and clean it out. I will do that. While I have it off I will see how much pressure and flow I get at crank. I did not look at the bowl while it's cutting out but will do...

This was converted from 6V to 12V and the distributor "looks" ok. The coil is fairly new but I know that is not much to go on.

There is oil in the air cleaner.

I'll post an update Monday. Thanks all!
 
ford3 said:
Ken is right , alt of things could be wrong, so check all the easy things first, then go to the harder things, my advice for what its worth
Click to expand...

Good advice like this is always worth gold in the right situation.

Thanks Ford 3
 
Do NOT use a rubber gasket under the glass bowl. Use a new cork one.Also flex line from pump to firewall could have a pin hole or crack and will not leak gas but will suck air when running. ken ct.
 
Keep in mind that intermittent problems can be electical in nature. Folks talk about 6- volt coils and 12-volt coils like a coil knows what voltage it will work with. A coil that is made to work on 12-volt without a ballast resistor in one with a primary coil designed to take more heat dropping the voltave internally. They will work but I prefer a tried and true coil that is wound for lower voltages and uses a ballest to take the heat externally. Condensers (capacitors) are crap now days. The best ones to get are the NAPA Echlin brand but you still may get a bad one now and then. If I was changing over to 12-volt, I'd use a 56 Ford Coil and a stock ballast resistor for a 56 Ford. The stock 8BA condenser will work with this combination just fine.
 
Carburetor Rebuild Kit on the way!

It is definitely a fuel delivery issue. I am able to reproduce the issue and when I spray starter fluid in the carb, it takes right off. I took the fuel line off to see how much fuel came out of the line when I crank it over. It was not as much as I thought but this was just my opinion. It put out about 2 ounce in about 30 seconds. - Estimate-

I have a rebuild kit coming and will post the results.
 
Points, condenser, coil, distributor cap, leads, plugs.

All things it could still be, so don't rule anything out yet. did you notice anything obvious when you stripped the carb? Blocked jets perhaps?

When the car was converted to 12V, was a new coil fitted? a 12V one? should it have an external ballast?

In my experience, any problems that come on as the car gets warm have been ignition related.

One other thing, is the fuel tank breather blocked?

I hope fitting the rebuilt carb does fix it, I'm just throwing a few thought joggers in there in case it does not.

Mart.

Edit: only just watched the video. Hmmmm. Blocked main jet or jets?
 
Mart,

I just got it on the road. It must have had blocked jets. It runs well with throttle and I am still working on the idle- kind of jumpy. It used to idle better even before the rebuild.

I started at 1-1/2 turns out on the idle adjustment needle and dialed in the idle screw. - I'll keep tuning......:)

Is there an inline fuel filter that would look correct but do a little better job than the glass bowl?

Thanks guys.
 
By the way, don't for get this little gem.....:o
 

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Hutch07 said:
Mart,

I just got it on the road. It must have had blocked jets. It runs well with throttle and I am still working on the idle- kind of jumpy. It used to idle better even before the rebuild.

I started at 1-1/2 turns out on the idle adjustment needle and dialed in the idle screw. - I'll keep tuning......:)

Is there an inline fuel filter that would look correct but do a little better job than the glass bowl?

Thanks guys.
Click to expand...
1 1/2 turns out on the mix needles is too much,3/4 to 1 turn is normal for these carbs. 7/16" on the float level upside down. ken ct.:) My typo,should be 1 7/16". A pleated paper filter can be installed in the glass bowl. ken ct.
 
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