Weber 314, stock fuel pump, fuel delivery issue

[cedryck]

I am sure this has been talked about before. Turner engine, weber 341 ch, stock ignition, stock exhaust. New tune up, (points, condenser, timing) runs great, idles beautiful. Drive up a hill, push on pedal, close to floor, trucks bucks like a bronco. Thoughts, (electric fuel pump?) cheers,

[TeriAnn]

I am sure this has been talked about before. Turner engine, weber 314, stock ignition, stock exhaust. New tune up, (points, condenser, timing) runs great, idles beautiful. Drive up a hill, push on pedal, close to floor, trucks bucks like a bronco. Thoughts, (electric fuel pump?) cheers,

While you are troubleshooting never forget that electrical and fuel delivery issues have the same symptoms. If you think it is fuel delivery disconnect the fuel line at the entrance to the carb, put an empty container under the open fuel line and give the fuel pump manual handle a pump or two. You should see a strong flow of fuel out the line.

BTW, Weber's like 2.5 - 3.5 lbs of fuel pressure. Any more and fuel can leak through the float valve. On the other hand I have no idea what a 314 Weber is. I do a google search and come up with street addresses.

Did you say the problem only occurs going up a hill?

[cedryck]

Thank you Terri. I am not sure I have the weber number correct, it is the one that our hosts sell as a common replacement for a Zenith,
The problem occurs under load with gas on, my carb is old, and I thought possibly it needs some attention, float adjustment, or a an air leak, but,
I hear of a many people fitting an electric pump to make up for what lacks from a stock mechanical fuel pump. I am getting fuel from my mechanical pump but not a steady stream from pumping the finger plunger, only a dribble,
other suggestions?
sorry misspoke it is a weber 341ch carb.,

[slowmo]

I would check the float clearance. And I did install an electric fuel pump which completely resolved a vapor lock issue I was having. This after I replaced the original fuel pump with a mechanical fuel pump...which did nothing to improve the situation. I am glad to be rid of the mechanical one.

I think it is 34 ICH. I have one too. The kit is cheap and easy to install. All that said I am struggling with what I believe is a carb issue as well...so feel free to ignore my post.

[cedryck]

not going to ignore any post here on these trucks, I will check and rebuild the carb, but friends here who drive these cars hundreds of miles more that I do, like from CT to Vermont, and New Hampshire, swear by adding or replacing the mechanical with an electric,
thanks, will check my float,

[TeriAnn]

I hear of a many people fitting an electric pump to make up for what lacks from a stock mechanical fuel pump.

Why is it that so many people decide that a mechanical fuel pump is not good enough to provide fuel to a carbureted engine? :confused: At least 90% of the car companies in the US used mechanical fuel pumps to provide fuel for their carbureted engines. This includes Ford, GM, and Chrysler as well as Land Rover four cylinder engines. They didn't install mechanical fuel pumps because they didn't work properly.



I am getting fuel from my mechanical pump but not a steady stream from pumping the finger plunger, only a dribble,
other suggestions?

What you are saying is that either there is a restriction in the fuel pickup or lines, the sediment bowl screen is clogged, the fuel pump diaphragm is bad, something is clogging the fuel valves in the pump keeping them from closing properly or the pump handle that rides against a cam lobe is badly worn. Only the last problem requires a new fuel pump.

Not knowing the vehicle I would first suspect a torn diaphragm, but I would take a shotgun approach and clean everything to make sure the whole fuel delivery system is in top shape.

Shotgun approach:

remove the draw tube on top of the fuel tank and examine the wire screen at the base. If it is at all clogged. clean it and reinstall with a new gasket.

Disconnect the fuel line between the fuel pump and draw tube and blow it out with compressed air. Do the same between the fuel pump and carb.

Remove the fuel pump then the sediment bowl (New gasket absolutely need to refit the bowl). Clean the sediment bowl. Pry out the filter screen and clean it. Undo the ring of screws around the side of the pump and separate the halves, being carefully to note which side the spring is on. Chances are there will be a hole in the diaphragm. Replace the diaphragm if you find any wear or damage. There will be two one way valves inside the pump, each facing the opposite direction. If there is any debris keeping one of the valves from completely closing the pump will not provide proper fuel pressure. Early fuel pumps have a metal valve retainer held on by a screw. Replace both valves with new ones provided in a fuel pump rebuild kit. Newer pumps retain the valves by peening over the metal around the valves. You are supposed to straighten out the metal, replace the valves and repeen the metal edges to hold the valves in place. Most people do not peen enough metal over the valves and a valve sometimes falls out. Personally I would not replace the valves on a newer style pump if they close properly and are not apparently damaged.

I have had bad luck with the replacement mechanical fuel pumps that are Asian copies of the original. About 15 years ago they tended not to produce enough fuel pressure. But that may have changed over time. If you want to replace the factory pump with a new one get our host's recommendation before buying a new one.

If you absolutely have your heart set on a replacing the mechanical pump with an electrical one get one designed to provide four pounds or less fuel pressure. Electric fuel pumps designed for American cars are set at around 7 or 8 pounds of pressure which is way too much for English and Italian carbs.

Electric fuel pumps do not suck well but push fuel well. This means the ideal location is near the fuel tank about even with the bottom of the tank. Some are quite loud so be sure to purchase any insulation kit that is available for the pump.

[o2batsea]

Bucking could be your alternator getting ready to die. Try having it tested. Also a bad condensor will throw hiccups. yes, they can be bad right out of the box cz it's likely eastern european or asian crap nowadays.
Fuel starvation would also behave that way. How old are the rubber fuel lines and do you run ethanol gas?

[cedryck]

Fuel lines good, no obstruction, I checked from tank pick-up to pump, no blockage. Yes new tune up parts, points, timing condenser.
Timing spot on, could be a dying alternator did not think of that, will have that checked.
Carb filter clean, so is jet. Plugs white, should be more brown will try adjusting mixture, really appreciate all of the banter,
Thank Terri and all of the others, cheers,