holley 4 barrel flooding

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diymirage

diymirage

HP@idle > hondaHP@redline
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hey guys

so i changed over my fuel system today and i ended up having the car towed home

it is a 71 duster with a 408 in it
it was a 5/16 dead end fuel system, set to 6 PSI

i installed a 3/8 fuel sending unit and used the 5/16 line as a return

the carburetor is a quick fuel 4 barrel, basic holley design

i put about 25 miles on it and then i came to a stop, stalled out and died

after several minutes, of trying to start it again (to no avail) i pulled the air filter and saw this




now, i KNOW a ton of crud came out the lines and so it would not surprise me if something got in the needle seat but that is a LOT of fuel dripping

in fact, enough fuel for me to change the oil before i attempt to fire it back up again

here are my questions for you guys...do you think crud is the most likely culprit or should i look elsewhere?

do you think i need to lower the float level?
(the fuel pressure is still set at 6)

do i need to pull the plugs and spray some oil in the cylinders?

anything else i could be overlooking?

thanks
 
My vote is something got into the needle and seat...
Easier to check that, than re-inventing the wheel.
 
Don’t even pull the bowl. Just take out the needle and seat. Once you take the adjusting nut off you can measure how much of the needle is sticking up, so you will be in the ballpark putting it back in. Just blow the needle out real good and test it to make sure that it is not sticky, like a metal bur on the brass. Then put it back in and go.
 
Looks like my Demon, kept shredding seat O-rings and propping needles open when I installed them. Something wasn't cut right in there.
 
thanks guys
ill check the seat tomorrow

any thoughts on changing the oil, and spraying some down the cylinders?
 
Cut the pressue to 4 or 4.5 psi.
Yes. Check the needle and seats too. Had one do that last year.
But if its both front and rear bowls at the same time, its likely too much pressure.
Out driving yesterday with that hot weather (for this time of year) was guanteed to make for high vapor and fuel pressures.
Clean clean clean
Then see if something can be done to reduce that reversion.
 
quick update in between church services
the oil is black, smells like oil and is at the bottom of the mark, so no signs of gas in there (though ill changes it anyway, since it is running a flat tappet cam)

i took the front valve out and didnt see anything but the rear float level did seem a bit high

i hit the throttle and saw 3 strong squirts of gas from the pumpshots, so there clearly is some crud in the carburator

i think i will pull it off and give it a good once over anyway
 
looks like I might have found the issue

(and she is dirty)

20200519_101423.jpg


20200519_102234.jpg


20200519_102238.jpg


20200519_102241.jpg
 
yep, dirt and needle seats don't get along very well
 
Ish !
Its probably in the other bowl too
 
'63GT said:
Ish !
Its probably in the other bowl too
Click to expand...
yes, the rear bowl was pretty dirty too

for some reason, that one had a plastic float, instead of the brass in the front

does that look damaged to you?
 
diymirage said:
yes, the rear bowl was pretty dirty too

for some reason, that one had a plastic float, instead of the brass in the front

does that look damaged to you?
Click to expand...

Yes, it does.
Worst thing is, it's bulging on the top, which will limit proper adjustment. It may bottom out or top out actually before the needle and seat close
 
'63GT said:
Yes, it does.
Worst thing is, it's bulging on the top, which will limit proper adjustment. It may bottom out or top out actually before the needle and seat close
Click to expand...

yeah, i pulled it out and it looks even worse
pretty sure its mangled and i can tell how it would hang up and cause the flooding issue

now to find out what part number to replace it with, and what caused this to begin with
 
Jeremiah said:
Do the floats float? They look mashed in like somebody blew compressed air into the bowl vents.
Click to expand...
it might float, ill try that in a minute
but the hinge point is so twisted, if it float it will bind up

not sure how that happened...unless fuel forced it up as it floated?

20200519_110702.jpg


20200519_110658.jpg
 
Looking at your video I see a lot of dirt and crusty stuff near the air bleed. You need to rebuild this thing with a kit. What is the make/model # of the carb? I
 
Jeremiah said:
Looking at your video I see a lot of dirt and crusty stuff near the air bleed. You need to rebuild this thing with a kit. What is the make/model # of the carb? I
Click to expand...
it is a proform 67200

she was definitely dirty

I got the float straightened out (mostly)
it looks like some dummy tried to adjust the float levep down while the bowls were full

so I'm guessing the flooding was caused by it being dirty, the bend float by operator error
 
got her all back together and purring like a kitten

only strange thing is, the fuel pressure is jumping like crazy, not sure why?

it didnt do that before
(it seems to level out a bit when i get on the gas though)

 
Last edited:
Excessive under hood heat will cause a large enough pressure difference to implode a brass float. I won’t put a brass float in a big block corvette anymore.
 
Dana said:
Excessive under hood heat will cause a large enough pressure difference to implode a brass float. I won’t put a brass float in a big block corvette anymore.
Click to expand...
wouldnt that kill the float?

this one got bent (presumable when i tried to adjust the level with the bowl full) but it is still airtight
 
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