The Stovebolt Site Forums The Shop Area Engine Shop hard starting after sitting a day or more; easy starting after

hi.

i searched and found some threads, and checked what was suggested, but still have the issue.

1957 3600

6 cyl 235

1 bbl carb that looks original.


owned this truck for about 4 years and it has always had this issue ( i just lived with it, but i want to fix it now):

say the truck sits unused for a day or longer.

when i then try to start it, it cranks and cranks and cranks but does not start until after a long time cranking. this cranking period can be anywhere from 20 to 60 seconds.

once it is started it runs fine.

i can let it sit an hour or two after that, and if i try to start it it will start right up.



the problem only occurs when it has been sitting for a day or longer.

previous owner did a lot of work to it.

looks like new wires, distributor cap; 'maybe' rebuilt carb.

i changed fuel filter and plugs, though they looked ok.


i thought maybe it was the fuel pump, but it looks newer. after letting it sit a day or two i disconnected the fuel line from the carb, cranked it once or twice, and fuel was pumping.

i thought maybe the battery did not have enough power to start the old engine, but i just put in a new battery and though the cranking is quicker, it still does not start right up.


where do i go from here given the symptoms?

thanks in advance.

From the "Troubleshooting" section of my website:

HARD STARTING, COLD


Difficult starting a vehicle that has been allowed to sit for a number of days (that will then start well the rest of the day) is often caused by modern fuel. Modern fuel begins to vaporize (evaporate) at a much lower temperature than fuel before the 1970’s. Once the engine is shut off, the fuel in the carburetor bowl begins to evaporate through the bowl vent. If there is no fuel in the carburetor, the engine will not start. Pumping the footfeed during this time simply prolongs the agony, as the accelerator pump will pump the fuel into the engine, but in amounts insufficient for starting. If you have this problem, try priming the carburetor by using an eyedropper and filling the carburetor bowl through the bowl vent prior to cranking the engine. If you do not wish to prime the engine, crank the engine for 15 to 20 seconds WITHOUT PUMPING. Then stop cranking, pump the footfeed 3 or 4 times, release it, and then reattempt to start the engine. Priming eliminates excessive wear on the starter. Another possible solution is the installation of an electric fuel pump. If an electric pump is installed, check local, state, and federal laws about wiring; and pick a pump with pressure not exceeding that of the original pump.

Jon.

Are you using full choke when you try to start the cold engine? Ideally, if the fast idle cam is working properly, you should pull the choke knob all the way out, and crank the engine with your foot off the gas until the engine fires, then quickly push the choke knob in partway to keep the engine from stalling from too much choke. Most people pump the gas pedal, or hold the throttle partway open and don't use enough choke on a cold engine.

If the one-way check valves in the fuel pump get a little leaky, the pump will have to fill the fuel line and the float bowl in the carburetor before the engine fires.
Jerry

Does the engine accelerate ok after it's started? Does the accelerator pump work?

yes, the engine accelerates as expected and the truck runs well.

choke is wide open when i try to start; the chob knob is pulled all the way out

Further to Jerry's post. Take the air cleaner off and confirm the choke closes all the way. I had the stud that holds the air cleaner on screwed in too far so the choke didn't close all the way. Mistake caused similar symptoms to what you report.

QUOTE "choke is wide open when i try to start; the chob knob is pulled all the way out"


???

If the choke knob is pulled all the way out, then the choke butterfly valve should be completely closed. If the knob is all of the way in, the choke butterfly should be wide open.

Have you tried priming, which will tell us if there is gas in the carburetor?

Jon.

ooops, i had it backwards... long day....

i will let it sit overnight and then try priming. i will also check the choke with the air cleaner off, and report back.

thanks all!

On your next cold start, remove the air cleaner and hit the carb with a shot of starting fluid. If it starts immediately that tells you that you're losing fuel somewhere, probably draining back out of the carb, or boiling out after shutdown as carbking suggested. A transparent fuel filter near the carb also will show you if there's any fuel in the line when you crank.

BTW, you don't by any chance have a Pertronix points-replacement ignition in that, do you? Their older models used to have that idiosyncrasy.

"i thought maybe it was the fuel pump, but it looks newer. after letting it sit a day or two i disconnected the fuel line from the carb, cranked it once or twice, and fuel was pumping."

You have had the truck for 4 years. The fuel pump isn't new anymore. Your symptoms are screaming "dirty check valves" to me.
Have you done anything to the fuel tank since you bought the truck? Your check valves may be gummed up from varnish in the tank being dissolved by 10% ethanol gas. Ethanol is an excellent solvent for varnish which would normally stay put on the inside of the tank if the old formula gas was still used.

Another possibility is that you may have a partial restriction in the fuel line at the bottom of the tank from debris settling there. This will make the fuel pump work much harder/longer to gas up to the carburetor.
Carl

FWIW, long cranking times are common with these old critters. Carbking was dead on in his first post of the tech tip. My '38 and '53 are both that way. I don't bother to prime. I just make sure the battery is charged, connections are clean and go for it.

I have done this for a long time after my truck has sat for more than about 2-3 weeks. Remove the air cleaner and spray a mist over the top of the carb for 1-2 seconds, and it always fires immediately. I figure this is much easier than hard cranking on the starter.

Also, a few years ago, I was told by a starter/generator/alternator rebuilder to never crank for more than about 3 seconds at a time. Cranking for extended periods (8-10 seconds) burns up the internal wires and connections. Don't ask me how I know...

Last time i ran into this problem, inreplaced the fuel pump and it was all good. Check valve or the diaphram was leaking,allowing fuel to siphon back...you could remove the fuel line off the carb and see if you have fuel when you crak eng over..if not ...try fuel pump..they dont last forever. Esp if the truck does more sitting than driving....

update from test today.


truck sat for two days without being started.

i pulled the choke knob all the way out.

i pulled the air cleaner off and verified that the choke was engaged and plate closed.

i turned the key to on and pressed the start pedal.

truck started within 2 seconds. what the.....huh?

it never started up so quickly like that (when sitting for days) since i have owned it. after my initial shock I was pleasantly surprised.


the only thing different, that i can think of for this test, is that i tried starting it with the air cleaner 'off'; i have not done that before. i then put the air cleaner back on and it started right up - as it usually does after an initial start - so the opportunity had passed to see if the air cleaner is involved with the issue.

now, maybe i just got lucky for some other reason (not the aircleaner). so, the next test will be to try the initial start, after performing the choke validation, AND with the air cleaner on, after sitting for 2 days. I will report back.



thanks again for all of the replies and great advice!

Remind me which air cleaner you have again? Our factory oil bath was quite dirty when I got it. You could also tell it was left loose on the carb for some time in it's lifetime. It has chafed into the carb a little and can interfere with the choke if pushed all the way down.

Lindsey makes a good point, check the distance the choke knob comes out with and without the air cleaner on, it could be a simple interference problem.

I'm no expert, but I think you have a great point. Vehicles perform much better when driven regularly. I've noticed that with my 1953. When I drove it to high school and was driving it daily, it was a pretty smooth runner and very few issues, but I always suspected the block needed rebuilding because it would puff a little blue smoke on cold starts. But when I left for college and two moves, job changes over the next few years etc, and the truck sat for years covered up in the garage, things went to crap quick. There were a couple of periods where it went 2-3 years without even being cranked. So now that I have a fresh rebuilt 261 in it, I intend to drive it more and at very least, crank it every 2 weeks and let it get to full running temperate for 20 minutes or so just to keep things moving.

It's not just engines that suffer from inactivity. Nothing hurts a brake system worse than long periods of non-use. Drum and rotor surfaces rust, and rubber parts get dry and leaky. It's a little tougher to get the brakes up to operating temperature than engines- - - -that takes a few trips around the block to do!
Jerry

update from second test today.


truck sat for three days without being started (instead of 2 days like the last test)

i pulled the choke knob all the way out.

i pulled the air cleaner off and verified that the choke was engaged and plate closed.

i put the air cleaner back on this time (it is the oil bath type), instead of leaving it off like last time.

i checked to see if there was any interference with any linkage or cables to/from the carb, but there was plenty of room; nothing was touching anything it shouldn't..

i turned the key to on and pressed the start pedal.

truck started within 2 seconds. hmmmm....


as stated previously, this truck, for the last 4 years or so since i had it, never starts up in 2 seconds after sitting for a day or two or more.


well, if "it ain't broke" we can't fix it and for now "it ain't broke" so nothing to be done .



thanks again for all of the replies and good advice and support with the issue.


i will report back if the problem comes back OR if i find something out.

We fixed it using a Vulcan mind meld from the collective. Your welcome.

It could be as simple as a piece of crud which may have been holding a check valve open has finally worked itself free, or the crud floating around in the bottom of the tank moved away from the hole in the bottom of the tank.

I'm going to chime in because I have a similar problem. Usually, if I crank within a couple of days she will start up fine. If she goes a week or so without running, she will turn over till I run the battery down without even sputtering. The carburetor bowl is vented to the atmosphere. That bowl doesn't hold a lot of fuel. It doesn't take long, especially in hot weather, for that fuel in the bowl to evaporate. It takes awhile to fill that bowl back up, with that old diagphram fuel pump. So, the engine turns and turns and turns. So, I've learned that if I haven't cranked her in more than three or four days, I must remove the air filter and pour about a shot (ounce or more) of fuel straight down the carb. She will fire up and purr like a kitten if I do that.

I'm going to chime in because I have a similar problem. Usually, if I crank within a couple of days she will start up fine. If she goes a week or so without running, she will turn over till I run the battery down without even sputtering. The carburetor bowl is vented to the atmosphere. That bowl doesn't hold a lot of fuel. It doesn't take long, especially in hot weather, for that fuel in the bowl to evaporate. It takes awhile to fill that bowl back up, with that old diagphram fuel pump. So, the engine turns and turns and turns. So, I've learned that if I haven't cranked her in more than three or four days, I must remove the air filter and pour about a shot (ounce or more) of fuel straight down the carb. She will fire up and purr like a kitten if I do that.