Vannin' Home Forums General Discussion Generic How To ..... IF I don't start the van every few days, I must add gas to the carburator ?

Here is the situation:

1. There is DEFINITELY gas in the tank this time (don't ask how I learned that invaluable lesson)

2. The fuel pump is brand new and seems to work great.

3. The fuel lines have been blown clean.

4. The van starts every day with no problems.

5. BUT if I let the van sit for about 2 weeks and never start it, when I eventually do start it, it does NOT start. Instead, I must add a little gas to the carburetor and then it starts right up and the problem disappears until I let the van sit for another 2 weeks.

Anybody have any simple solutions/what the problem is?

Check your accelerator pump. When you hit the gas does it send a little squirt of gas down the carb? If not you might go ahead and get a carb rebuild kit.

Somebody told me that the new gas being sold has ethanol. A corn based alcohol added. I was told this will gum your lines and add a residual shellac to unused (heated) engine and carb components.

To solve the above problem, they SUGGESTED I install a secondary fuel filter between the carburetor and the fuel pump closest to the fuel pump. Do you think this has any likely benefit of solving the problem?

I just replaced the normal fuel filter but that didn't solve the problem. I was just curious if there was any benefit to installing a second fuel filter. It obviously isn't expensive.. but was curious if there was any benefit or if this would almost certainly not solve the above problem (of the van not starting after sitting for 2 weeks unless I add gas to the carburetor).

Sounds like your fuel bowl is leaking, or air is getting in, causing the fuel inside to evaporate over time. Try first tightening all of the screws holding the top of the carb on. Also, check the fuel line at the inlet to the carb to be sure everything is snug. Check for fuel leakage under the carb.

If it still happens, consider rebuilding the carb and replacing all of the gaskets. A 2nd fuel filter will most likely not solve anything.

Could be a tiny pinhole leak in the fuel line also ... causes a lack of pressure to hold the fuel in place allowing it to run back to the tank, and needing the primimg... Also is the choke flap on top of the carb shutting all the way when cold sitting to hold the fuel in the carb and then cracking open just a little when you press the pedal once to start the van ??

Try cleaning the pick up in the gas tank, and strainer, and make sure you found ALL the fuel filters. The fuel pump has more power when engine running than when just cranking on the starter. so if theres a blockage in the line the pump isnt running fast enough just with the starter. Make sense?

is it a chevy van? I had that problem in my chevy van and the cure is to take apart the carb and look underneath the two halves and you will see what looks like a v that leaks slowly. you can drill it out and put plugs in then epoxy it or just clean it off and epoxy it well. I did this and cured my problems. boy, I just looked at the date on this thread I assume he got it fixed by now. oh well, it is good for anyone with this problem as it is very common.

mrcampbell: Thanks for the reply... Yah, my posting is a bit old, but I STILL have the same issue. I'm unfortunately a mechanical moron and too chicken to "take apart the carburetor." Likewise, taking off the doghouse to add the gas to the carburetor is too much work every time I want pull it out of the garage (which is rare). So this is what I do when I haven't started the van for a week or so (which is generally the case since I rarely drive it):

I turn the key and pump the gas as fast as I can possibly pump it with my foot slamming on the gas pedal repeatedly. I let it crank for about 4-5 seconds. I then stop trying to crank it (since I don't want to burn out the starter). By the 3rd time I do this, the gas finally gets to the carburetor and it starts up.

Too bad there isn't a way to 'pump' gas into carburetor without having to try and start the van and burn out the starter... kind of like in a lawnmower. A lawnmower has that little button/bump you hit 3 times before you start the lawnmower. Too bad my van doesn't have that feature! ;)

Question: Do you think it is better to pump the gas really fast when trying to start it, or is it better to turn the key and instead keep the gas pedal almost floored? Which way gets gas to the carburetor faster?

Thanks in advance for your help.

Replace all the fuel lines(rubber). Then make sure the well plugs on the carb are "tight"-as in punch & hammered tight.

There is. Install an inline electric fuel pump

example : https://www.summitracing.com/int/parts/atx-e8012s

This is what I have to say about it... my forty cents if you will. We have the same problem... when it is hot out. When the temps are cooler to cold, one pump of the pedal and she fires off like a champ. After much investigation, thought, experimentation, etc. we've decided that it is an evaporation issue. Right now, in FL, dead of summer, if we let her sit a day... one pump and she fires off great. More than that and it takes progressively longer to fill the bowl and get her going again. Used to think it was leak down or other issues but since she consistently can sit for weeks at a time in the colder weather with little trouble finally concluded it was evaporation.

Lastly, I second the inline electric pump. Although we don't plan on going this route. Instead we just know in the heat we've got to crank her to fill her and then pump and start. It is what it is.

Good luck.

BlairW: Thanks for the info on the Electric Fuel Pump thingy.

Um, feel free to laugh, but is there like an idiots guide on how to install that thing? I know ZERO about auto mechanics... and am not a huge fan of playing with fuel related stuff... Think its a simple job or am I better off getting somebody that has a clue what the hell they are doing?

By way of example, I looked on the comments section of that page where they are selling the Electric Fuel Pump thingy and it says, "This pump has a max output of 9 PSI, so a regulator would be needed if 9 PSI is more pressure than your carburetor is designed for. Many carburetors require 4-6 PSI so in many cases a regulator is recommended." My engine is definitely NOT stock.



I have NO idea what the answer is....

Hmm... is there perhaps an easier solution? I honestly only start the van up a few times a year.... so its not a huge issue.. I just hate to have the starter crank 3 times before I can finally get the fuel into the carburetor while I FURIOUSLY pump the gas pedal a gazillion times as quickly as possible while its trying to start... and like I said... It seems silly to go through all the time/trouble to remove the dog house to add fuel to the carburetor.. particularly since I'm only going to drive it around the block anyway... but at the same time.. I'm not sure how smart it would be to go this route either.

THANK YOU GREATLY IN ADVANCE FOR YOUR ONGOING HELP. SINCERELY APPRECIATED.

OK- you need to become familiar with the basics of carburetor operation. I'm not being rude, just noting that many people these days don't know how to properly live with a carbureted vehicle.

(1) Fuel pump operation. Old mechanicla fuel pumps operate off a lobe on the camshaft or an eccentric that bolts to the front of the cam. Mechanical fuel pumps typicaly make 5-7 PSI or so, which works out great beacuse most carbs only need 4-5 PSI of fuel pressure to operate. The fuel supply PSI needs to be that low because the carburetor float actually functions as an on/off valve controlling the fuel flow. When the carburetor float bowl (discussed below) gets full of fuel, the float lifts up and presses the inlet needle into the inlet seat and stops the flow of gasoline into the float bowl. Too much fuel pressure and the fuel pump will overpower the float and cause fuel to overfill the carburetor float bowl leaking to a massive fuel leak into and onto the engine.

(2) Carburetor construction. The main point here is the float bowl. The float bowl acts as a small reservoir/holding tank of fuel for the carburetor to feed the engine. Contained in the float bowl are the float (the on/off switch for fuel flow), the accelerator pump, and the main jets and main metering rods (if so equipped). This is an oversimplification since there are many designs of carburetors with different fuel metering arrangements, but for the purposes of this discusion that is enough detail. The fuel in the float bowl serves an number of functions. It provides a ready supply of extra gas to be squirted into the carburetor throat when you step on the gas and operate the accelerator pump. It also stores a small amount of fuel on which the engine will run when first started and the fuel pump has not drawn fuel from the tank yet.

(3) Gasoline evaporates. All non-marine application carburetors all have vents to the atmosphere for a variety of reasons (none of which are important here). These are typicaly called the "bowl vents." If the vehicle sits for more than several days, chances are the fuel in the float bowl will either completely or partially evaporate out the bowl vents. In the bad old days, we all just lived with it. Garages and car interiors often smelled like gas because the cup or so of gasoline left in the carburetor evaporated and the fumes got everywhere, including into the "fresh air" intake for the passenger compartment. Beginning in the late 60s, car manufacturers began experimenting with ways to trap the evaporating gas and make it able to be reused. Early methods included trapping it inside the air cleaner, but the generally accepted industry standard became the charcoal cannister.

Charcoal canisters work by collecting the gasoline vapors that escape from the carburetor (and fuel tank on later models) and storing them in a charcoal matrix to be reintroduced into the carburetor when the engine starts back up. This reduced pollution, make starting easier, eliminated the nasty gasoline smell from garages and interiors, and saved money since you were no longer buying gasoline and just letting it evaporate. The charcoal canister usually has one to five hoses on it. Early models just had a hose that went to the bowl vent on the carb. Later models had two hoses that went to the bowl vent(s) and another port on the carb as well as a hose that went to the vent on the fuel tank. The most advanced designs had numerous hoses that went to many different places. All these hoses were the drawback to charcoal canisters. Many auto enthusiasts and "mechanics" who did not understand what all the hoses were for, were intimidated by all the hoses, thought all the hoses were messy, or just thought auto emissions didn't matter, disconnect the systems or removed them or levelled baseless criticisms against them. The truth is charcoal cannisters help your car run cleaner, be more efficient, and have absolutely zero negative impact on performance.

(4) Proper carburetor operation. "FURIOUSLY pump the gas pedal a gazillion times as quickly as possible while its trying to start" is not the correct way to start a carbureted engine, especially one that has been sitting. Doing this can actually cause the internal parts to wear out prematurely. Here is how a properly functioning carburetor on a daily driver street driven vehicle should operate. If the vehicle is cold, you should be able to depress the accelerator to the floor once, release it, turn the key, and have the car start. Some models require the one pump followed by holding the accelerator pedal 1/3-1/4 of the way dwn while turning the key. In some circumstances (very cold areas) you may need to pump it twice or even three times, but most places only need one pump. The engine should start easily and go immediately to a high idle that drops within a minute or two (longer in cold climates).

When you pump the gas that first time, several things are happening. Externally, the choke valve should be closing fully and the fast idle linkage should be getting set to hold the thottle partially open. Internally, the accelerator pump operates and squirts gasoline into the intake to richen the mix and make starting the engine easier.

(5) What happens when the float bowl is dry. When the float bowl is empty, on the first pump of the accelerator pedal the choke will be set but the accelerator pump will have no fuel to pump into the engine. Depending on the type of carburetor you have installed, the acceleretor pump plunger may be of a design that has a rubber (actually, not rubber but some fancy synthetic material. A long time ago they were leather, but those days are long gone) cup that goes up and down in a small cylinder in the float bowl that pumps the gas into the carb throat. When the float bowl is dry, that little rubber cup scrapes along the edges of its cylinder and wears itself down every time you pump. This is why pumping the pedal many times while you wait for the float bowl to fill can damage the internals of the carb.

(6) The right way to start a carburetor if the float bowl is empty. If you know the float bowl is empty, the best way to start the engine is to remove the air cleaner and fill the float bowl with gasoline or carburetor cleaner through the bowl vent tube. If that isn't an option, pump the gas ONCE to set the choke and fast idle, then crank the engine for a while to give the mechanical fuel pump a chance to pump some gas up into the float bowl. This can often take 30-45 seconds of cranking. After the first 15-20 second of cranking, pump the gas pedal once. If the engine doesn't catch and run, keep cranking and pump once every 5-10 seconds untli the engine catches and runs. Never crank for longer than about a minute. You will wear out the starter motor and the battery. If the engine doesn't start after cranking for a minute, let it sit for about 30 seconds and try again.

(7) Installing an electric fuel pump. Installing an electric fuel pump is not difficult and might actually be a good idea for you. With an electric fuel pump you can prime the carb with gas before ever touching the accelerator pedal. Here are Holley's instructions on how to install one of their aftermarket electric fuel pumps intended to work with a carb. I strongly STRONGLY recommend you follow those instructions and install a safety shutoff. http://www.jegs.com/InstallationInstructions/500/510/510-12-801-1.pdf

Hopefully this helps de-mystify the carburetor and helps you solve your problem. I strongly recommend you get a factory service manual for your van and read it to learn how everything works. That will help you operate it better and keep it around longer.

Excellent post Reed!

Reed: Thanks soooooooooooo much for taking the time to respond in such detail about my 74 van. SINCERELY, I had absolutely no idea I wasn't starting the van properly by pumping the gas a bunch of times. I also didn't realize that me pumping the gas (before I even insert the key), is starting the process of getting fuel to the carburetor. I foolishly thought I had to crank it as I was pumping. Doh!

I have a hunch a LOT of people are making the same mistake as me. Just an idea, but if you ever get a chance, you should create a short Youtube tutorial video explaining how to start an old 74 van. Seriously. I know it sounds goofy.... but I had nooooooo idea after all these years.

As for ME installing the fuel pump, I think I'm going to pass. I'm too chicken and once I saw mention of the "safety shutoff," I am definitely too chicken. I'm a SCHMUCK. If I can't even start the van up properly, it probably ain't a good idea for me to fiddle with electrical stuff and fuel. But perhaps I'll have somebody install it down the line in the future for me.

Once again... thanks VERY VERY much... and if you do create that Youtube video (and I SINCERELY hope you do), please send me the link. Many thanks again.

For what it is worth, I have a 76 Dodge pickup truck. A previous owner removed the charcoal cannister and I haven't replaced it yet. If the truck sits for more than a couple days the float bowl is dry. I have to crank it for a good 30-45 seconds before enough fuel reaches the carb and it will fire off. This is normal. I hope to add a charcoal canister in the future to alleviate this problem. Eventually I want a turbo and fuel injection, but that is a different thread.

My 2 cents .... When I go to start my 4x I open the door put in the key (which is higher than my head) turn the key & it starts...Then I get in after a couple minutes of warm up. I never touch the gas pedal as I dont get in it to start it.

My '92 is a little lower & I sit in the seat to start it ..... sameo sameo turn the key no pedal.


Yes both of my vans have a charcoal evap canister

Are your vans fuel injected or was Chevy still putting carburetors on 92 and 93 vans? I would be shocked if your vans didn't at least have TBI. Ford and Dodge were all FI by 88. I don't know much about Chevies.

Yes they have TBI ... so I guess I added to a carb thread ?

Yeah, this thread is all about hard starting on a carbed vehicle after it has sat for a few days. Easy starting is one of the great benefits of fuel injection.

Is this still equipped with the original Rochester Quadrajet carb? Not sure? Post a picture of it the next time you have the cover off.

I have this hard starting problem. I had the Quad jet rebuilt, he fixed several problems, drilled out the choke and replaced the rod. Sealed the bottom from leaking, replaced all the parts in it.
Still really hard to start.
I suspect the cannesters could be plugged or even the lines could be cut that run to it.
My thoughts are to run an electric pump with a switch. Turn it on let it fill the bowl , start engine and turn it off to run.
Any thoughts on doing it this way? Will it work?.
My 1947 BeechCraft Bonanza had a hand pump 3 to 5 pumps then start slowly pump while starting till the engine pump caught up then secure hand pump. Worked perfectly.

How does it run when it finally starts,lots of things could cause this problem,what is the quadrajet on?.Have you got an old purge canister hooked up to the float bowl,if so disconnect the line at the float bowl.
The only other thing I feel it could be is the choke is junk and misadjusted, possibly a very low float level

Did he put an accelerator pump in it? Or leave the plunger off,you should never have to prime a q jet..the fuel from the bowl is going somewhere,after reading your post again I am leaning toward an accelerator pump

It can be more involved than that. A mechanical pump has a one way valve that prevents fuel from draining backward. I just had this problem on one of my projects. The fuel pump was almost new but when you blow through the outlet you can feel the air passing in reverse. Not a lot but that teeny bit was all it needed to cause a problem when sitting more than two days. I got another new pump from the parts store and tested it. Stopped up tight. No more long crank time trying to get fuel up to the carburetor.