Today's Weird Question

[tony barnhill]

Okay, here's today's question:

1. Fuel pump is pumping gas yet bowls are empty (checked to make sure it was pumping by holding gas line in a bucket).
2. Removed top of both bowls/floats & pumped gas into them directly from the gas lines (rear carb line flows first & front carb line doesn't flow unless rear bowl is full) .
3. Replaced tops/floats onto full fuel bowls (&reconnected fuel lines to bowls).
4. Started engine & ran until it died - opened bowls & both were empty.
5. Disconnected fuel line from bowls individually & both pump fuel.
6. Filled both bowls again, hooked up fuel line & engine runs until both bowls are empty.
7. Yet, fuel is pumping out into a bucket when lines are disconnected from bowls.

Why are the bowls running empty when fuel is being pumped from rear of car to them?

 

[Steve_S]

Bad float valves. Try blowing through them and working the valve up and down. The valve should open and close freely.

 

[DrEntropy]

Needles stuck to seats... 's all it CAN be.

Do I get a prize? /bcforum/images/%%GRAEMLIN_URL%%/laugh.gif

 

[DrEntropy]

Ratz!

Steve wuz quicker...

 

[Steve_S]

Gotta be quick round these parts! /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

 

[Baz]

Why are the bowls running empty when fuel is being pumped from rear of car to them?

If it's not the above, this happened to me just recently. The vent pipe from the float lid was blocked (old rubber, or canister), keeping the pressure inside the chambers. Kinda like a coke bottle with a straw and a clay lid.
Just a possibilty if the floats are OK.

 

[DrEntropy]

Thought of another one. Bizarre and unlikely in this case but: if you leave carbs lyin' around down here for long without capping the fuel inlets, you can expect to find a mud wasp has decided to inhabit the tubes!

 

[Mickey Richaud]

Thought of another one. Bizarre and unlikely in this case but: if you leave carbs lyin' around down here for long without capping the fuel inlets, you can expect to find a mud wasp has decided to inhabit the tubes!

And that would be the clay lid Barry wuz speakin' of!

 

[rick_ingram]

Same thing with my 1968 MGC...I traced the flow of fuel from the tank all of the way to the bowls...car won't run except when given a shot of starting fluid...then guess how long.

This thread will be of some assistance to me.....thank you!

 

[ccougill]

it never fails, if one person has a problem somebody else has it also. As old as these cars are there is rarely a new problem

 

[DrEntropy]

Same thing with my 1968 MGC...I traced the flow of fuel from the tank all of the way to the bowls...car won't run except when given a shot of starting fluid...then guess how long.

This thread will be of some assistance to me.....thank you!

Pop the lines off the bowls, and one at a time remove the bowl lids and pull float pins, remove needles, clean needle & seat, reinstall. All should be fine then if everything else is 'good-to-go'. "gummy gas" is the usual cluprit here. If the car sat too long, the tube from bowl to jet can also be gummed. If fuel gets to the bowl but not to the jet look to those lines.

 

[Bugeye58]

Tony, see the thread on waking a sleeping MG on the Autoist web site. /bcforum/images/%%GRAEMLIN_URL%%/devilgrin.gif
Jeff

 

[DrEntropy]

MUUHAAHAAHAAAA!!!!!

/bcforum/images/%%GRAEMLIN_URL%%/smirk.gif

 

[RonMacPherson]

Make sure your float bowl vent passageways are clear.

 

[rick_ingram]

Thanks!

 

[tony barnhill]

Yep, yep, yep & yep....Had already checked most of the things mentioned: Floats are good, needles/seats good/clean, new gas, no wasps or dirt dobbers, took vent pipes off - no change.

New idea though: will check tubes from bowl to jet tomorrow.

did notice that the rear carb bowl doesn't get completely empty, there's about 1/4" of gas in it when the front carb bowl is bone dry.

 

[jlaird]

Tony, try the fuel pump with the tops off the float chambers but with the tops hooked to the fuel line. If fuel is not comming out the line it is the needles. If you hold em up right you can play with the float to see that it is working correctly.

 

[DrEntropy]

Sounds like he's past that'n, Jack. Now it's only the jet supply lines and jets themselves left.

Shooting some aerosol carb cleaner "backwards" from the jet orifice to the bowl with one'a them li'l red "straws" could clear out the goo, Tony.

 

[tony barnhill]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Tony, try the fuel pump with the tops off the float chambers but with the tops hooked to the fuel line. If fuel is not comming out the line it is the needles.[/QUOTE]

Interesting idea, Jack...looks like no fuel is getting through the tops!

I have Grose jets in both tops & the floats appear to be working correctly...time to bring the tops to the workbench & see what's up inside them!

 

[jlaird]

Think not maybe, fuel is to the carbs just not into the carbs. Only one answer stuck needle valves. Was just pointing out a way to check only takeing out 6 screws.

Of course Tonys answer may well be replace the car. hehe.

If this is the red B, don't you dare.

Bet we could fix it in 10 min or less Doc.