The Stovebolt Site Forums The Shop Area Engine Shop Truck stutters a bit then stops - Then starts sort of easy

A couple of weeks ago, I drove the 1950 3600 with the original 216 engine about 100 miles or so and once during the trip it stuttered a bit but then not again for another 100 miles or more. Last week it did it again and when I took the foot off the gas, it quit and would not start again until I popped the hood, gave a spritz with some ether and then it would go. It has continued to do this every few miles or less and while it will fire up immediately with the ether, I have to do it a few times to get it stay running. Then I will drive a bit and it will do it again.
I first thought that the filter was letting junk get by since there is almost always some kind of red sandy material in the filter bowl. It is not magnetic so I do not think it is rust and actually looks more like sand. Anyway, I took the filter off and made sure the filter element was seated properly and then cleaned out the bowl. Truck started right up after that with no ether. I was going to take it out for a drive but decided to pull the carb off and clean it out good to be sure that the problem was fixed. Once I got the carb off I was surprised to see very little junk in the bowl - it was quite clean. I still took the various bits out and cleaned it all with carb cleaner and put it back together. I needed just a quick squirt of ether to get it going after that and it idled smoothly. I was able to get a half mile down the road before it started to act up again, stuttering and then just quit. The glass bowl in the fuel filter remains about half full like it always is.
I am thinking my next effort will be to pull the fuel pump off and make sure that is clean as I have found lots of junk in it before. The pump is new last year. I did put a rebuild kit in the carb last year as well and it has run quite well since then.
Anybody have any ideas what might be going on?

Gas cap

You haven't mentioned the cleaness of the tank.That rust coloured stuff is coming from somewhere. If it's a cab mounted tank,pull the sender/float out and have a look into the tank.

The tank was removed three years ago and run through a hot tank. The shop that did it said it was in good shape, to good to consider the epoxy coating. However I do believe that is where the crud is coming from but can't imagine what it might be. I figured that it would slowly go away with each tank of gas and as long as I cleaned the filter bowl out periodically I would be good to go. I had other issues with it last summer but seemed to have resolved those.
The gas cap is the one that has been on it since about 1979 when I bought it and drove all the way across the continent without this kind of issue. And I have driven it several thousand miles the past two years with the same cap as well. It did sleep for 20+ years though and I just got it going again three years ago so I knew there would be some issues.

Sounds like trash is sloshing around inside the tank, momentarily clogging the down pipe opening. If it a partial restriction, the engine will idle just fine since the demand for fuel is low. Once you step on the gas, fuel demand will exceed supply. One time I filled my tank with gas and got a free cup of red clay with it. Stopped up the works pretty good. Check the tank for debris.
Carl

I'm thinking like Carl on the momentary clog.

You could not have a rusty tank but rather you got a bad load of gas.

Years ago I had a 78 Nova 250 3 spd column, car started to act as if it was starving for gas.

Check the filter, it was dirty. Changed it and ran fine for a while. Same symptom appeared. Sure enough cut open the filter dirt again. Replaced filter, good to go.

Third time no hinting of filter plugging up partially it just trapped a huge load of crud and the motor stopped.

Replaced that 3rd filter and no more problems.

I would get the tank cleaned out to be safe.

Thanks for all the comments.
I'm headed to the auto parts store to buy a new filter element and try that.

A new filter did not fix it. I am thinking there is still some blockage in the carb that prevents sufficient gas getting in to keep it filled. I neglected to mention that the first time this happened I removed the glass bowl on the filter and gas squirted out - it was under pressure (engine off). Time to take the carb off again!

A new filter will not prevent crud in the tank from plugging the hole in the bottom of the tank.

Big Ditto, what Carl posted.

And, the fuel pump will develop pressure on the carburetor side (but, not be able to deliver gas, due to a possible stoppage at the outlet on the fuel tank).

Your fuel tank outlet is on the bottom of the tank - right?

if you think it is the carb take that sucker off, blow it out good with an air hose and see what happens, might even use a spare carb if you have one, you might also check to see if there is any where in the gas line that has a small hole or crack in it, that might be causing a burp. I know , one would think if there was a hole in the gas line you could find see it or smell it real quick... not always..

is it possible that it is not a fuel problem but a break down in
the coil or else where when it gets hot it is hard to start back up..

Thanks again for the responses.
I took the fuel tank sending unit off this morning and took a look inside. Fortunately the outlet of the tank is directly below the sending unit and with a strong flashlight, I can peer right down into the brass outlet fitting and see all that bright shiny brass. I do not see any bits of debris sloshing about on the bottom of the tank either. My next step will be to remove the fuel line and pump and make sure they are all clear. And yes, I took the carb off and cleaned it out again and blew it out with compressed air. All seems good there.
I do not think it is a spark/coil issue since when it quits, I can start it again right away with a bit of gas poured into the carb intake - everything is still hot, or at least as hot as it gets during a 1/4 mile drive.

You have eliminated the possibility of tank debris. Now I would look into the possibility of vapor lock. Are all your fuel lines in the original configuration and location?
Another thing to check is the fuel delivery rate of your fuel pump. You can remove the line from the carburetor and have a catch can for the fuel to go into. You can use the starter to drive the pump with the ignition off.
Carl

The fuel lines are original save for the piece that goes from the added glass bowl filter to the carb. I have the truck jacked up now and am going to take the fuel line off and blow it out as well as inspect and clean out the fuel pump. Maybe I should try your suggestion first though as if it is pumping fuel like it should, it would seem that the problem lies elsewhere.

I did the fuel pump check but unfortunately I have no experience with fuel pumps to gauge it with. To my eye though, it looked quite sporadic and insufficient. I disconnected all the fuel lines and blew them out as well as taking the pump apart to clean it although it did not look bad inside. I had to run to the store before it closed and will now put all the stuff back together and also do a pump check before I connect to the carb to see if there is any change.

It is a diaphragm pump so the fuel will come out in spurts. Need to have the fuel volume checked.

Hey Gazz, how about an old easy shade tree suggestion? I know you've had the carb off several times and blew it out, but have you tried the old vacuum trick? Take the air cleaner off and also remove the stud that holds the air cleaner on. Start it up, e brake on, in neutral, and get under the hood and grab the throttle lever with one hand and rev it up to about 1000-1500rpm and hold it there for a moment while with your other hand and w a shop towel smother the air horn opening to kill the engine. Do this several times.....the theory being that you're trying to suck any foreign debris or contamination thru the idle circuit and power circuit. Can't begin to tell you how many times I've done this over the years with great success, on cars, motorcycles, lawn mowers, etc. It's worth a try.....good luck. Dave

Okay, I got it all back together yesterday early evening but had no chance to test drive it. After blowing out all the fuel lines I did a check for pump operation. Looks like a spurt of gas with every revolution of the cam and it seems like enough gas for idle speed. I'll be driving it around the block this morning to test out the recent work and let you all know what I find.
Thanks again for the help!

A successful round trip of about 16 miles with no issues. Made a couple of stops and it started properly and did not quit on me for the entire trip. It seems to be one of those things were it just wanted some attention as I found nothing that I thought be a problem, just took it all apart and put it back together.

Good deal! Gald you got things working.