My 77 Spider leaks gas from carb after the engine is hot. This apparently comes from a leak at the air jet. With the air cleaner off, I see gas percolating up even after the engine is off. It only seems to come from the primary jet ( LHS slotted head when viewed from front). Spraying with carb cleaner helped but didn't cure problem. Is there a fix a novice can tackle?
Thanks.
Gas leak at carburetor air jet
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majicwrench
Re: Gas leak at carburetor air jet
A bit of gas bubbling thru jets on a hot carb is likely normal. If it is pissing out you have a issue with needle/seat and float. So how much is leaking??
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Scotsman
Re: Gas leak at carburetor air jet
Hello Magicwrench
Thanks for your info.
It leaked about a spoonful or so but enough to stink the garage and have the wife muttering darkly.
I flushed with carb cleaner and added cleaners to my gas. Seems to have helped the leak. That's the good news.
Bad news is I seem to have screwed up my fast idle and I am getting minor backfiring and stalling coming down from high revs. I tried to reset fast idle using the push button but revs drop immediately to low idle . I checked electrical connections to electro valve, push button, clutch pedal switch and 3/4gear on trans. All OK. Ground Ok. Pressing push button interrupts electrical flow from EV but does not hold revs above low idle, about 800. Backing out fast idle screw doesn't seem change anything. Now that I've stopped most of the leak, the LH barrel on my Weber 32 ADFA 11 seems to get no gas over a wide range of throttle settings. Should it? (Now you know my ignorance of engines!).
Other good news is the car runs well enough for short trips and it is summer.
Thanks for your info.
It leaked about a spoonful or so but enough to stink the garage and have the wife muttering darkly.
I flushed with carb cleaner and added cleaners to my gas. Seems to have helped the leak. That's the good news.
Bad news is I seem to have screwed up my fast idle and I am getting minor backfiring and stalling coming down from high revs. I tried to reset fast idle using the push button but revs drop immediately to low idle . I checked electrical connections to electro valve, push button, clutch pedal switch and 3/4gear on trans. All OK. Ground Ok. Pressing push button interrupts electrical flow from EV but does not hold revs above low idle, about 800. Backing out fast idle screw doesn't seem change anything. Now that I've stopped most of the leak, the LH barrel on my Weber 32 ADFA 11 seems to get no gas over a wide range of throttle settings. Should it? (Now you know my ignorance of engines!).
Other good news is the car runs well enough for short trips and it is summer.
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So Cal Mark
Re: Gas leak at carburetor air jet
gas bubbling from jets is not normal. Sounds like you need a phenolic spacer to insulate the carb from heat as a start.
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majicwrench
Re: Gas leak at carburetor air jet
The last place i would start is with a spacer. If you have a problem, fix the problem, not add some new bandaid.
Scotsman, sounds like you have several issues, so not sure where to start. You've mentioned the fuel, does it spill out on the ground?? Flood the engine so it's hard to start? a flooding issue could certainly contribute to the stall on decell.
How
So does decell valve work?? When you push button, does idle go up?? (You may have to blip throttle to help it get up)
These valves tend not to work for various reasons as the cars get years on them.
Even without decell valve, car should not stall on decell, the valve is more for emissions, so not sure I would worry bout it at this time, although a functioning valve will help reduce backfiring.
"LH barrel" is secondary, usually not fuel going thru it, don't worry bout it, fix other things.
My thoughts so you don't confuse me/you/us too much, pick one issue, and let's address that issue.
Keith
Scotsman, sounds like you have several issues, so not sure where to start. You've mentioned the fuel, does it spill out on the ground?? Flood the engine so it's hard to start? a flooding issue could certainly contribute to the stall on decell.
How
So does decell valve work?? When you push button, does idle go up?? (You may have to blip throttle to help it get up)
These valves tend not to work for various reasons as the cars get years on them.
Even without decell valve, car should not stall on decell, the valve is more for emissions, so not sure I would worry bout it at this time, although a functioning valve will help reduce backfiring.
"LH barrel" is secondary, usually not fuel going thru it, don't worry bout it, fix other things.
My thoughts so you don't confuse me/you/us too much, pick one issue, and let's address that issue.
Keith
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Scotsman
Re: Gas leak at carburetor air jet
Hello Magicwrench and Keith,
Many thanks for your insights and suggestions. I am no mechanic and I no longer have a local mechanic who knows the engine. I bought the car new so after 38 years of fun driving I am now trying to understand its workings to keep it running.
The small, very smelly gas leak at the air bleed above the fast idle stopped after running with carb cleaner in the gas. It may have been due to a small block or, as was suggested, to a hot engine from a long run on a very hot day.
I now apparently have lost the fast idle function and get minor backfires when decelerating quickly. When I depress the Electrovalve switch before or after high revs, the revs do not hold in 1800 range but drop quickly to low idle 900 revs. The electrical circuit to EV, EV switch, clutch and 3/4 gear tests OK.
I'll start with the fast idle EV as Keith suggested. How do I test this? If it is bad, can I temporarily swap it for the similar looking EV in the EGR circuit? This EV lies on the same plate as the fast idle EV and switch.
Thanks again.
Many thanks for your insights and suggestions. I am no mechanic and I no longer have a local mechanic who knows the engine. I bought the car new so after 38 years of fun driving I am now trying to understand its workings to keep it running.
The small, very smelly gas leak at the air bleed above the fast idle stopped after running with carb cleaner in the gas. It may have been due to a small block or, as was suggested, to a hot engine from a long run on a very hot day.
I now apparently have lost the fast idle function and get minor backfires when decelerating quickly. When I depress the Electrovalve switch before or after high revs, the revs do not hold in 1800 range but drop quickly to low idle 900 revs. The electrical circuit to EV, EV switch, clutch and 3/4 gear tests OK.
I'll start with the fast idle EV as Keith suggested. How do I test this? If it is bad, can I temporarily swap it for the similar looking EV in the EGR circuit? This EV lies on the same plate as the fast idle EV and switch.
Thanks again.
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majicwrench
Re: Gas leak at carburetor air jet
I don't know if a 77 is the same as my 72, so will look at a diagram for a 77 if I can find one.
On my 72, pretty sure vacuum is what does the work to hold rpms up, do you have vacuum to valve?? If so, when you energize valve, does vacuum go thru valve??
Like I said, will try to see how a 77 is arranged tomorrow.
Very fun that you are the original owner.
On my 72, pretty sure vacuum is what does the work to hold rpms up, do you have vacuum to valve?? If so, when you energize valve, does vacuum go thru valve??
Like I said, will try to see how a 77 is arranged tomorrow.
Very fun that you are the original owner.
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So Cal Mark
Re: Gas leak at carburetor air jet
these cars were originally equipped with a heat insulating spacer under the carb, so the last place you would start is oem. Boiling fuel and leaks from jets is not normal
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Scotsman
Re: Gas leak at carburetor air jet
Yes, fast idle EV regulates vacuum to diaphragm device. The original lines look bad and I can't feel much vacuum so I will replace.
Thanks
Thanks
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Scotsman
Re: Gas leak at carburetor air jet
Found and fixed a bad connection on fast idle EV. Running well again. Many thanks for your help.