Fuel pouring from drivers side carb... Stuck/sunk float? Thoughts, people?

mrtask

Well-Known Member
#1
Noticed a very distinct whiff of petrol and that my car didn't want to idle without stalling, popped the hood, fuel pouring from the overflow pipe out of the drivers side carb (V8, HIF6s). Tried tapping the carb body with the handle of a screwdriver, to no avail.
I suspect float trouble. Sunk or stuck. ISTR that is a carb-off-the-manifold job, and needs a seal kit. If anybody has any helpful suggestions please chime in!
What parts do I need to order, and from who? Wait, am I jumping the gun? I suppose I need to have it off and on the work bench before I start ordering parts... Post advice and moral support please.
 

Demetris

Well-Known Member
#2
Sometimes it's just some dirt that sticks to the needle and doesn't allow it to seal properly.
As you say, you have to take the carb off to find out. It's a simple enough job, so, nothing to worry about.
 

cobraboy

Well-Known Member
#3
When you remove the float chamber base from an HIF6 the square section O ring seal will grow and you can never get it back again. However when I had trouble and no new seal I got a scalpel and cut the seal, offered it up to the seal recess and cut again, then joined with superglue. It worked and sealed perfectly.

I only offer this up as a get you out of a muddle solution.

Before pulling the carb check you fuel pressure is below 3 psi.
 

PepijnWK

Active Member
#4
A reply on an old topic but I have the same thing. The fuel is pouring out of the carburettor where the fuel goes in. It poures out of the overflowpipe. I just replaced the float seats and nbeedles by new ones but that did not do the trick.
I have HS6 carbs and a mechanical fuelpump under the car near the gastank. I suspect that it is to powerful. I used to have an injection unit on the car but I removed it and replaced them by carbs.
Questions I have
Should I replace the fuelpump by a less powerfull one? ( facet or something) Can I just ad a fuelpressure regulator in the line?
How much pressure should the pump or regulator be?

I see facet pumps cilindrical ones and small square boxlike pumps. Which one do you recommend?

Thanks in advance for the answers!!
 

cobraboy

Well-Known Member
#5
I use a high output Facet cube pump and a Malpassi pressure regulator. When using HIF6 I needed to have this set to less than 3 psi to stop flooding, I do not know how much pressure HS6 will tolerate, you will have to see.
I now run around 4.5 psi with a 4 bbl carb. The beauty of having an adjustable regulator is you have the flexibility to choose the pressure you want.
You could start by using a pressure gauge to see what the current output is. Also you could run a pipe into a bucket and work out the gallons per hour. If you have an adequate supply then fit a regulator.

For example
Malpassi Petrol King Regulator For Carburettors
 

PepijnWK

Active Member
#6
thanks Cobraboy!

I do not really understand the system! the float only stops the overflowtube?





In the photo above the top of the floatchamber.
1=fuel entry
2=fuel towards other carburettor
3= overflow

if you blow at 1 closing 2 with finger then when lifting the float nr 3 will be blocked by the float needle.

I really am puzzled by this system because why would there be an overflow tube? There is a fuel return line so what is the purpose? I am also puzzled why it started leaking. as mentioned I renewed the floatseets and needles but the first carb where the fuelline enters keeps overflowing!

I checked wheter the returnline was blocked but it was not. I blew air through and could heart the bubbles in the tank.

So it might be the high pressure of the pump.....
 
#8
lucky .you I get odd fuel dumping despite new jet/needle and flat level checks etc. looking at dirty fuel ..not so much particles but more a 'mist' so assuming minuet debris /plaque etc (tank) building. up on needle tips and preventing closing fully at times. it only lasts few minutes and but u get a real whiff of fuel when travelling. now and again. was using mechanical and facet style pump. mechanical now removed and blanked off. still get odd whiff of fuel spill. agree comment why have spill overflow onto road when we have a return line? checked my return by blowing air in pulses with filler cap open. no bubbling in tank and each blast of air gets a corresponding pulse of fuel emitted from fuel line to carbs as though pressuring fuel supply line? going to try next week a separate fuel tank and pump mounted in passenger floor section ( with fire exitinguisher etc ) and remote switch /battery supplying fuel direct to carbs .. a 10 mins run up country lane ought see if ist my fuel supply /pump installed/problem . then I guess its drain tank and remove etc :( clean and line
tank possibly . sigh.
 

PepijnWK

Active Member
#9
checked my return by blowing air in pulses with filler cap open. no bubbling in tank and each blast of air gets a corresponding pulse of fuel emitted from fuel line to carbs as though pressuring fuel supply line?
Are your lines mixed up?Three lines two fuel lines Main and reserve and one returnline. Return line should create bubbles in the tank when air is forced through.

I got a spare pump of a friend. I will try that one tomorrow. fingers crossed
 

cobraboy

Well-Known Member
#10
The return line has a restrictor where is ends at the tank end, this gets blocked easily and needs clearing with a small drill to pull out the muck and not push it back up the pipe where it will block the restrictor again.
Restrictor is in this union.

IMG_3261 (2).JPG
reserve pickup inside filter
IMG_3263 (2).JPG
Main tank pickup no filter
IMG_3262 (2).JPG
 

PepijnWK

Active Member
#11
I was just thinking. I know ther are floatbowl covers/lids without the overflow tube. I could offcourse go for those. But I think the fuel pressure would be high so the pump has to be replaced anyway i think. But I really do not see the purpose of it when there is a return line... Any thoughts?
 

colnerov

Well-Known Member
#12
Hi, The purpose is if the float valve doesn't close off, the pump will just keep filling the float chamber and then push the fuel up the jet and straight into the inlet manifold. The return line has a restrictor either at the carb end or tank end, so the jet is the route of least resistance. So the overflow pipe is even less resistance.

Colin
 
#13
wasn't aware restrictor at tank end . tank over half full so will run it down as much as I dare.. then split connection and see if a wire probe works then blow with a air line again. Thanks for info.
 

PepijnWK

Active Member
#14
ok Understood.
I just took the pump from a friend and bolted it on but the pump was leaking....... tomorrow I will try again with more patience. Not very funny exchange a fuelpum inlet tube above your head. Fule drips (pours) along your hand, arm elbow, armpit straight until the pelvis al filled with petrol....... I smelled like petrol quite a bit!.
I made some pictures of the connections in my car:




as you can see the fuel ump is attached to the main line
the place of the reserve line there is my return line and the line intended for the return line is blocked. Since the reserve thing is not working at the moment.

I think it does not make a difference to change the reserve and return does it? They are both part of the same exit of the tank and use a joined iron tube
 

PepijnWK

Active Member
#15
Before reinstalling the pump i tried to install a different lid without overflow:


added a float and adusted it:


result: it overflows!!!!

closer inspection learned that there was a tiny hole in the lid that acts as a overflow hole:



so I took the pump and used it with a jerrycan :



this worked so I took my timea and replaced my pump with the one from my friend. Result: it works!!!! no overflow any more!!!!

my old pump:



specs on internet:
pressure PSi: 43,5
pressure 3 bar

so that is way to much. What I still do nounderstand why this problem appeared. I have these carbs mounted for some time. I did not notice the fuel loss or smell........
I must be getting old or something happend. Well it works now. See if I can keep the pump otherwise I will have to buy another pump.
 

PepijnWK

Active Member
#17
Sharp observation Cobraboy! The lines are ( (almost) all new! This piece was old indeed. It is a tube with lining in it. Ir had cracks in the outer layer but was not leaking. But if the lines are that dried it they should be renewed! You are absolutely right.
 

PepijnWK

Active Member
#18
Well the pump eventually leaked. The housing was not petrol proof. So I bought a new pompo and installed it. Works great. No regulator needed unitil; now.

 
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