MTFCA Forum

Hi all,
Yesterday after working on an axle for 2 days for a rebuild, I decided to take the Tudor out for a ride to get some needed reward and fresh air. Drove around the neighborhood a little to insure that the car's running well. All good; drove downtown to the public parking area and had swarms of people looking, taking pictures and asking questions.
When I decided to leave, the car started coughing, bucking and stalling as I drove the 1/4 mile to my house. I stopped traffic each time and then... flashing lights. A wonderful, cute, blonde police officer (looked to be 17 years old) was there for traffic safety. I called my buddy and he came with his truck and we towed it about 100 yards to my driveway. Thanks Pip (his real name).
My question is, what could cause the bucking, stalling, etc.? It would start, run a few seconds, then start bucking and quit.
Background: I rebuilt the Holley NH and sediment bulb, restored cowl tank, new plugs and wires, Ron's coil boxes, new Anderson timer, plenty of gas. I adjusted the fuel mixture at 1 1/2 turns. I have had the car running on short trips of about 5-10 miles in the past year, no problem. It runs on mag roughly, but it runs. At times yesterday, when it was about to stall, I pulled the choke and it seemed to smooth out. Could it be debris in the fuel line? An air leak somewhere? disconnected timer wire? stuck float needle or other jet? I plan on checking out plugs, wiring/timing and taking apart the carb. Any suggestions would be very appreciated from you fine folks, Thanks. Have a great Labor Day.
John

If you have a tank under the seat, I would suspect maybe the fuel is getting low. If it is a cowl tank, not so likely low fuel. Would the drive home be uphill? Then I would also suspect low fuel.
Most likely cause would be low float level or something stuck in the needle seat float valve. Our modern fuels tend to jell up if not used within about 3 months, so if the car was setting a long time that could be a problem.
Hopefully it was not caused by your forgetting to open the fuel valve.
Norm

Check the sediment bowl and the screen may have to be cleaned out

I suspect a dirty timer.

I drove the car last about 2-3 weeks ago. At first, I had forgotten to open the fuel shutoff and tried moving the fuel mixture all over the place. I got it running when I realized my mistake and got it running. But it started acting up when driving it home. Would messing with the air/fuel mixture have caused the problem? Tudor with cowl tank is 1/3 full, so it has gas. I'll check the timer as well.
Johh

John... If there is an added filter after the sediment bowl, just eliminate that and have a clear line between the bowl and the carburetor... And don't forget to clean out the sediment bowl and screen.

It has been my experience that with the symptoms that you describe, the cause is most often fuel. If you had a skip, I would suggest electrical, but your symptoms point to something that affects the entire engine, not just one cylinder. I would check any filters and sediment bowls, then if necessary after taking a fuel sample from the carburetor float bowl, pull the float bowl and see what the fuel looks like. I was stuck by the side of the road a couple of years ago, and when I pulled the float bowl it was about half-full of crud. I cleaned it out and drove home normally. Of course I then went through the entire fuel system.
The fact that when you enriched the mixture it ran a bit better shouts fuel starvation to me.

First of all, Messing with the fuel mixture could be your problem. 1 1/2 turns may be fine for starting and warming up, but it may be too rich once the engine is fully warmed up.
You are allowed to adjust the fuel mixture at any time when driving the car. There is no one perfect setting. The same is true of the spark timing.
I usually start my car with the mixture open about 1 1/4 turns. As the car warms up, I adjust it leaner. My car generally runs best when warmed up with the mixture open from 3/4 to about 7/8 turn. Once the engine is started, I adjust the spark timing to suit running speed and load.
Be sure your choke is opening fully when it should, which is any time the engine has run for half a minute or so. When warm, the engine probably needs no choking to start.

Your car should run better on magneto than on battery. If you are running on battery, you may need to keep the spark advanced quite a bit once the engine is started. If you have a generator, adjusting it to show as much as 7 amps with the car moving at 20 MPH or more may help the ignition perform better. I suggest getting the magneto in good operating condition and using it.

Beyond that, I'd check the timer, timer wiring, and fuel bowl and screen. (Be sure the gas shutoff is fully open)

I agree that your T (or any stock T) should run better on MAG then BAT. Your coils are transformers. Transformers don't work with Direct Current, thus when on BAT, the mechanical oscillators (the buzzers) on the top of the coils are converting your car's DC into AC. It does take some energy to operate the oscillators, and you only have 6 Volts to work with. On MAG, the coils are getting as much as 30 Volts AC and the oscillators are not working, therefor they are not drawing current. When I start my T, I am switching to MAG the instant the engine is running, and the difference in the way it runs is amazing.

Thank you all,
I just cleaned out the sediment bowl and found dirty gas and some debris, like tiny hair. The screen inside was a little clogged, but still a little open. Once I did that it started and ran. But it's not warmed up. Can't do anymore now, but I'll clean out the carb bowl. Could be some surprised there.
At least I'm on the right track. Thanks a million folks.
John

I think you've found your problem. It takes very little to restrict or clog a non-pumped fuel system. (But the fuel pump never goes out)
Once you get going again, try adjusting the mixture and timing as you drive for best results. This is best done out of traffic on a rural road. When you get your car running its best, you'll know it.

I was going to say "open the drain on the carb and see if you have good flow" but it looks like I'm late the to party. Also - do yourself a favor, grab a sharpie or a file and warm your car up, go for a ride - when it's fully warm mark or cut a notch in the mixture knob at 2 oclock. That's "warm" - if it's cold, turn the knob back to 10 oclock, that's where you start it cold.

I'm glad you found the problem. One thing which could cause this to happen which happened to me on a tour. A number of cars stopped at a certain intersection with more than one gas station. I filled up with gas and later on that tour had a similar problem you had. Later I found out that all the cars which had used that station had problems. The ones who went to the other station had no problems. That gas station actually had some sediment in the gas tank. This can even happen if you happen to fill up right when the tanker is filling the station. It can stir up sediment at the bottom of the station's tanks. Fortunately, I was able to drain the sediment bulb on my car and it ran OK after that the rest of the tour.
Norm

I never fill up from a station that has just had it's tanks filled. Water and crud below the stand pipe can get all stirred up if the station hasn't been vigilant about cleaning it out. Made that mistake at an airport once and drained about a quart of water and crud out of the two wings tanks after the plane had set for a bit. Fortunately I found the contamination before I flew it.

My dad made the mistake at a local gas station many years ago..... car made it about two miles and died. Six fuel injectors had to be replaced.