The Stovebolt Site Forums The Shop Area Engine Shop Mysterious stalling at idle

Hi All
Well, the weather was irresistible this weekend and I snuck my 55 First series 3100 with a 235 inline out for a fun drive around town after completing my honey do list. After driving her with no issue for about 30 minutes, I brought it home and left it running in the driveway in neutral with the parking break engaged to keep it from rolling down the gentle slope of the driveway. I left it idle for about 3-5 minutes and it quit running on me while I was in the garage fiddling with something about 5 feet away. I went to restart it and it just would not start despite my efforts at pumping the pedal for a few times, various manual choke position, etc. I let her sit for about an hour and I got her to cough and fire up. I immediately drove it into the garage and parked if for the night. next morning, I went in and gave a turn to attempt to start her up. she started right up and I swear she laughed at me.

When it initially died, I thought it may be a vapor lock, but the weather was a cool 50-55 degrees, and the temp gauge was normal, and nothing out of the ordinary was seen with hood up.

I then took the debug path of I am not getting spark or not getting fuel. When I could not start her, I pulled the oil bath cleaner off and manually moved the throttle and saw a whiff of smoke indicating to me that it was getting fuel, so I tried again at that point and it finally started after several more tries and pumps on the accelerator ( this was right after initial stop, not next day)

Obviously, I will not leave it idling for long periods, but I am hoping some of you can suggest some things for me to test, as I suspect this will happen again, perhaps more so as the weather gets warmer in Michigan

the truck is 95% stock to my knowledge, with the engine having an expected 1954 casting number, single barrel carb, oil bath cleaner and otherwise Spartan engine bay, just the way I Like it - a racing friend of mine wonders if it might actually have been an electrical malfunction due to heat in the engine compartment since it was sitting and idling for so long

Any suggestions to test and or theories would be most welcome

Joe

Hi Joe,
I don't know if your problem is the same as mine, Ihave a 47 loadmaster with a 54 235. It would stall after a long idle. I replaced the complete fuel system because I could not get rid of debris in the fuel system. I tore apart the fuel pump and found it full of junk that would periodically come loose, since then I have had no problems. Good luck.

how is the spark when it is hot? When an ignition coil starts to go bad, it will sometimes stop working when it gets hot, then it cools down enough, it will start working again. It may have been that idling after a good run, it was hot and got a bit hotter under the hood idling and stopped giving you spark.

It's possible that your float valve in the carb is or was leaking slightly when closed. Maybe crud in the seat. During normal driving you won't see any bad effect as you'll be using the gas faster than the leak. During the extended idle, the leak slowly overfills the bowl and one result can be flooding the engine to death, and making it too rich to easily restart. This depending on the carb, how well its sealed and the leakage rate. It also can be an intermittent problem that goes away as the crud washes through the seat or moves around in the valve.

A float valve that won't close with a bigger leak can often result in a shower of gas all over your hot manifolds and engine compartment, with obvious serious fire danger. I'd second the note to check out the fuel lines.

My W-1 Carters will start to ice up if the weather is cool and damp. It hasn't died, but the bases and manifold sure get wet.

A failing condenser will shut the engine off. ..then if you.wait for a few minutes it will start again until the condenser over heats again....and then it shuts down again..........my 2 cents...

Hi All
Thanks for the help so far - I will do some more testing this weekend if I can - I now have two suggestions about the coil - I did not realize that it can fail at high temp - I was going to heat it with a heat gun I have and see if I get spark - I dont know any other way to test it.

The condenser suggestion above is also interesting. If I remember correctly, the condenser is just a capacitor, and i am guessing the dielectric material in it fails with high temps?

Ignition coil and condenser are also pretty cheap, so I might just replace them and test the old ones off vehicle - For now, I will make sure I shut down when in a driveway waiting - has not happened at a long traffic light yet - that is my real worry