What causes carb float bowl to drain (1 Viewer)

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I have a carb that has the above symptoms.... just on a quick check I noticed fuel drooling in the secondary via the venture at a slow rate and at the same time seepage and bubbling from the shaft on the secondary acc valve circled in red in the pic.... any connection?? don't know as of now.. we shall see next week......
042-01M-41.JPG
 
Anyone learned more about this subject? Mine seems to evaporate out of the bowl quicker than normal.
 
mine was the o-ring from the sight glass. hope this helps however I no longer have my 60.
 
2017 bump. Looking for any additional ideas on this topic.

My situation:
84 fj60
- OEM carb, recent SOR core swap
- starts easy after sitting for up to 12 hours.
- runs great, runs strong
- after 24 hrs full choke plus two pumps starts it but dies immediately, starved. Repeat a second or third time and it runs normal plenty of fuel
- after 72 hours brutal getting started. Above scenario x 5. Float bowl empty
- after 1 week. I must crank the engine for a very long time before attempting start. Eventually it fires fine and runs flawlessly.

No actual cold starting above, I’m in SoCal.

Tips? Advice?
 
TomJoad said:
2017 bump. Looking for any additional ideas on this topic.

My situation:
84 fj60
- OEM carb, recent SOR core swap
- starts easy after sitting for up to 12 hours.
- runs great, runs strong
- after 24 hrs full choke plus two pumps starts it but dies immediately, starved. Repeat a second or third time and it runs normal plenty of fuel
- after 72 hours brutal getting started. Above scenario x 5. Float bowl empty
- after 1 week. I must crank the engine for a very long time before attempting start. Eventually it fires fine and runs flawlessly.

No actual cold starting above, I’m in SoCal.

Tips? Advice?
Click to expand...
It will be mostly empty after a day or less, not totally but quite low, its normal. Are you pulling the choke then pumping the pedal three times then turning the key? Try that then luk how it starts....
(I see now your saying no cold start). Time to consider your fuel pump then, esp if its stock. You can pull the soft line from the pump going up to the carb and stick it in a bottle and try starting the truck... easy test if its pumping fuel like it ought too or not.
 
Last edited:
Just resort to the "pre-start technique" and it will (should) fire right up every time... even after setting for a month... (if there's no vacuum leaks and the carb is working correctly).

If the engine has difficulty starting after a day of sitting (or longer) because the float bowl is empty, pre fill the float bowl with fuel BEFORE attempting to start it.

  1. Don't pump the gas pedal, don't pull the choke
  2. Turn the key and crank over the engine 5 revolutions then release. You can hear the cycles. This will fill the float bowl.
  3. Pull the choke all the way and pump the gas pedal quickly all the way to the floor three full pumps. Fast down, easy up.
  4. Wait 20 to 30 seconds (helps the fuel vaporize in the manifold)
  5. Turn the key and start the engine with your foot off the pedal. The engine shouldn't need any extra pumping of the pedal.
  6. Let it warm up before driving it.
  7. Make sure your carb fan works
 
grant5127 said:
I have a carb that has the above symptoms.... just on a quick check I noticed fuel drooling in the secondary via the venture at a slow rate and at the same time seepage and bubbling from the shaft on the secondary acc valve circled in red in the pic.... any connection?? don't know as of now.. we shall see next week......
View attachment 112926
Click to expand...

Does anyone have a solution to this problem, leaking secondary accel pump?

Thanks.
 
TomJoad said:
2017 bump. Looking for any additional ideas on this topic.
No actual cold starting above, I’m in SoCal.

Tips? Advice?
Click to expand...

Welcome to Kalifornia gas.

RFG (Reformulated Gas) is even worse in So. Kalif because of AQMD. New gasoline is formulated to run exclusively in fuel-injected cars. RFG is way more 'lighter' than conventional gasoline, plus all the crap that's in it to help lower various emissions, so it either capillaries out of the float bowl when it sits or evaporates.

Yours may be exacerbated by dirty fuel filter, weak fuel pump...

All my carb'd vehicles act the same as yours (I'm in L.A. area), and I just know I'll have to crank for a bit before the float bowl refills and it starts. I pretty much do as OS suggests with a good warm up.

Impact of Today's Fuels on Carbureted Engines - Engine Builder Magazine
 
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Juggernaught said:
Thank you, Yota. I think you've read every carb thread on Mud.

My list of these (seemingly simple) hacks is growing unmanageable. I'm about ready to surrender, sell off the stable, and buy a Taco and be done with problems for 8-10 years.
Click to expand...
Yes I have way too much free time on my hands.
FYI, tacos are almost as awesome as cruisers. They actually wheel pretty good. I’ve seen it in person.
 
I have a friend that killed and engine from a brand new fuel pump over pressurizing the the fuel to the carb which led to fuel seeping past the pistons and thinning down his oil.

I would smell your oil and make sure it doesn't smell like gas or your engine will DEAD soon.
 
Did hear from one of our carb gurus on Mud that ethanol in our gas changes the properties making wicking/ siphoning more likely.
 
cruisedeisel said:
I have a friend that killed and engine from a brand new fuel pump over pressurizing the the fuel to the carb which led to fuel seeping past the pistons and thinning down his oil.

I would smell your oil and make sure it doesn't smell like gas or your engine will DEAD soon.
Click to expand...

Sounds like the return line was either clogged or connected incorrectly.
 
For the carbs that fuel is wicking out of, you could try wetsanding the aluminum. I usually like to finish up with 3000 grit.

Obviously, pinpointing where the RFG is dripping from would be helpful. Maybe grab a flashlight, some beers and watch.
 
Thanks for all the feedback and advice!

OSS, indeed cranking prior to start is a workable fix but I may as well install a squeeze bulb from an old outboard boat motor! I was hoping I could get this thing working well enough that starting wasn't SO rough. Good idea on checking the carb cooling fan... this should be running anytime the engine manifold is hot correct?

On some of the other ideas:
- Fuel pump deliver is fine. It's not a brand new unit but it delivers with no issue.
- Fuel filter is new Spike, Wouldn't a weak pump struggle to keep up at high RPM? Mine runs strong over 3k rpm.
- I haven't seen any seeping but I also haven't sat down to watch with 6 cold ones + headlamp: good idea.
 
TomJoad said:
indeed cranking prior to start is a workable fix
Click to expand...
, This isn't a fix, its a way of priming your carb fuel bowl prior to start up. I followed his directions when I first started up my truck after I got everything back together from a top end I did this summer. It was interesting to see the fuel creep up to the middle of the sight glass after about 10 or less times as he explained; it works. And I have rebuilt my carb fully and had it off more times that I want to say and honestly feel your carb will not simply retain enough fuel to the sight glass to be ready to go after 24/48/72 hours. It does slowly seep down thru the lower ports as mentioned earlier... Tho I am very much a novice and a female in this man's forum, I'll stand my ground and say your might be asking for too much from a 30 year old truck. Baby her, stroke her and butter her up. Its called foreplay. Attempting to start her (even in warm weather full time) doesn't mean she's gonna be ready as soon as you turn the key.
And no the carb cooling fan will not be running anytime the manifold is hot. It runs after the manifold has come to temp and you shut her down fully. It will run for maybe 10 minutes.
And if your fuel pump is not new and your questioning its delivery even remotely... pull the line up to the carb and stuff it in a bottle and then try turning the ignition, if it dumps in easily then its probably okay...
 
Also.... the carb you got from SOR. Do you know what ACC pump they installed? Oem or from a rebuild kit? Two vastly different pieces....
 
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