The Stovebolt Site Forums The Shop Area Engine Shop fuel pump not pumping fuel?

Well, got the truck running today, after the electrical and fuel problems just a few days ago. But now I have another fuel problem. I have a hose running into a tank and the hose is connected to the steel fuel line. The line is not blocked, and when I start the engine(getting fuel to engine by poring a little down the carb) the engine runs for about 20 seconds and then dies. As the engine runs, I can see the inline fuel filter's element fluctuating, which means that the fuel pump is trying to send fuel to the carb? But when I put my hand over the hose I can't feel any suction. I don't have very much gas in the container I'm using(2-3" enough to cover the hose end) so could that be the problem?

You need to check everything from the end of the hose to the carb. Start at the end of the hose and work your way toward the fuel pump. There is an obstruction somewhere in there, or the problem is your pump. It could be a inline filter plugged up. Keep looking... ain't it fun...

You have two, one way, valves in the fuel pump. As the diaphragm moves up & down it draws fuel in through one & pushes it out through the other. Pull the lines on both sides of the pump & turn the engine over while holding your fingers over both openings. If the suck side is sucking and the push side is pushing you have a blockage in the lines. If not the pump needs rebuilt/replaced.

Well, I'm pretty sure that there's not an obstruction in the lines since I pored some gas down the hose and then blew on the hose and when I checked the filter(which is new by the way) it had gas in it which was not previously there. Also, I filled the fuel pump up with gas and started the engine and I watched fuel come into the filter so the pump has to be good, so maybe something in the pump is blocked?

Is this a new pump? If you pull the line just after the pump and crank the engine over, it should be pumping a lot of gas. Is the float set too low?

This is the pump that was on the truck when I got it, not sure if it is original but it looks old. The float should be fine, it worked the other day just fine, and then when the sending unit pickup got plugged everything went down hill from there.

A very good chance the intake valve I mentioned is bad. As I said put your finger over the intake port of the pump & crank the engine. If you don't feel a suction you'll need to rebuild/replace the pump. If the exit valve is good it will pump the gas you put in the pump out but won't pump more gas in.

Maybe Marco has been sneaking across the highway at night dumping sugar into your gas tank!


Stuart

Yeah, but the problem is that Marco is a town. If what you said is true, then I have a lot more problems than a bad fuel pump! Tiny, I tried that a little while ago and didn't feel any suction, but I didn't have a helper handy and could only turn the engine by hand, so that may be my fault.

jdl,

I think if check you will find that Marco isn't a town, it's a unincorporated community.

Stuart

Are you researching me?

Fuel pump is good, lines are clear, what could be the problem? Oh, and the fitting on the "pull" side of the pump cracked when I took it off, anyone know where I can get one without having to order from an online vendor?

JDL: take the fitting with you to a parts store. Any decent one will have that fitting.

If the auto parts store doesn't have one a hardware store will. If you still have the metal line you'll be looking for a compression/NPT fitting. They usually have them in a display where you can visually compare your old one to the new one.

I thought all the fuel lines and fittings were inverted flare...maybe not.


Stuart

Hey JDL,

Does Marco mean Marco Island in Florida?

Nope, it's Marco Indiana. atomarc, the fitting I'm talking about is the brass fitting on the pump that the fuel line screws into. You screw the brass fitting into the pump, then screw the fuel line fitting into the brass fitting.

The original fitting in question was 1/8" male pipe on the pump side, and 5/16" inverted flare on the fuel line side.
NAPA has these, I bought some a few weeks ago.

Grigg

Just bought the brass fitting at Jim Carter..Cost too much in gas to go to the store to buy it..

Keith

Thanks Grigg, I was hoping someone would tell me that. I'd rather go to the store and buy a 50 cent fitting then wait two weeks for it to arrive.

Try Weatherhead number 202x5, may be more like $0.92
Grigg

Just a thought.....the 54 fuel pickup has a pipe that goes up through a hole in the floor in front of the tank on the outside and then down into the tank through the sender unit assembly. I noticed that my fuel pressure was dropping as my new tank got down to 1/2 full or less. Also noted that there was some fairly large trash that had gotten through to my glass bowl filter just in front of the carbs. I attributed it to sloppy maintenance by the gas retailers at their pumps and added a filter between the tank and the pump. A little air pressure back through the line to clear the sock filter on the end of the pickup assembly seemed to clear things up. Trash in the valves on the pump will render it useless....also make sure your cap is vented. Don't know if this will do you any good, but it's the first glitch I've encountered in over a year of flawless operation with my 235.

Dave

Stuart I think you are probably right. It's been a couple of years since I've messed with my pump so I've slept a few times since. How do the politicians say it? You took my mis-statement out of context?

Just as fuel evaporating from the carburetor bowl leaves a residue in the carburetor bowl, long periods on no use allow the fuel to evaporate from the fuel line also leaving a residue which adhers to the side of the line.

When any portion of the system is modified (i.e. removing/replacing a carburetor, fuel pump, or tank, the fittings on the fuel line are disturbed, dislodging some of the residue.

A GOOD insurance policy is to flush the lines by connecting a hose to the line before the carburetor, and cranking the engine (with coil disconnected) for about 30 seconds any time fuel system maintenance occurs. Pump the fuel into a can. You can then filter the fuel, and dump it back into the tank.

Jon.

Is it possible that the jet inside of the carburetor is plugged? If you were pouring gas down the carb then the jet was not being used. Maybe you could fill the bowl up and pump the throttle to see if it is squirting any gas out.

Dellman, nope, when I first fired the truck up the pump had some gas in it(able to be seen going through the filter before the carb) and it was being used, so it is fine.

Anyway, my problems seem to be solved! Got the fitting at Napa and put it on, then messed with the hose on the fuel line and clamped it on this time, then stuck the other end of the hose in a gas can and cranked the engine over, and since the battery was run down too much to start, pulled the hose out of the can and fuel pored out so the pump is working. It probably just had some gunk in the pump intake valve and when I put my finger over the end and cranked the engine the suction pulled it through.

jdl,

This thread has gone on for two pages with lots of direction from folks on how to positively diagnose the problem.

I sure don't see how your most current revelation proves anything about whether the fuel pump is NFG or not.

Maybe I am missing something...being from California and all!

Stuart

I already said that it was good. I took off the line at the suction side and put my finger to the hole and cranked the engine. It had suction, so that proved that it was good. My "most current revelation" proved that the pump was good because no gas would be sucked upward out of the 10 gallon gas can. Example: Putting a garden hose in a water bucket. When you don't have any suction at one side, nothing should go up the water hose except to the level of the water, right? When I took the hose out of the gas can gas pored out, not just in a trickle, but in a stream, for more than 5 seconds. Plus, now, my truck ran for 10 minutes before I shut it off because of all the heat in the cab.

Good the hear! One step closer to driving it

One STEP? I just did that! Although it was only around the yard.