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Hard Braking - Engine Dies!
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Author:  bwhitejr [ Thu Jun 22, 2006 4:28 am ]
Post subject:  Hard Braking - Engine Dies!
When ever I brake relatively hard and come to a stop the engine will die. Also I notice if I come to a stop light that is on a decline the engine will die when you try to leave the light. Is this a sticking float? This is a standard transmission. Holley 4160.

Rant:
I tried to set the float level with the engine running. When you loosen the lock screw the thing sprays fuel all over the place and drips directly on your headers/ exhaust manifold. How the hell are you supposed to set the float level on a running Slant Six? I know it is a set-it-once procedure, but that is just poor design. Why isn't it set correctly at the factory? I tried resetting the float level only because I was cautioned a number of times in the literature. Now I think it is hosed.

At this point I need to pull the carburetor and reset the float level by turning it upside down and make sure the top of the float is level with the bowl.

bwhitejr
Author:  Sam Powell [ Thu Jun 22, 2006 5:23 am ]
Post subject: 
The only carbs that I know of that you can set the float on while running are the Holley race style carbs. Have you tuned this engine up recently? I know your engine boasts some healthy specs which suggest you care about it,but time can slip by and get away from us easily. It sounds like your engine needs a general tune up, which would include new plugs, wires, rotor, distributor cap, valve setting,and a carb rebuild. I suspect your problems will go away when you do this. Check your timing carfully when you tune it up, and make sure the timing is not retarded. My guess is the float is wrong, but this just might become the straw that breaks the camel's back under certain specific situations.
Sam
Author:  Pierre [ Thu Jun 22, 2006 2:41 pm ]
Post subject: 
The 8007 4160 I bought new came with the floats already set fine. Spraying all over sounds like something else though, maybe too high fuel pressure.... unless the float setting was really off.
Author:  DusterIdiot [ Thu Jun 22, 2006 3:21 pm ]
Post subject:  Pull the bowl...
If you pull the screw and it's dribbling a little gas that's correct...if you open it and it gushes then: the needle's stuck open, or the float is set too high, or worse the float has "sunk"...

Time to pull the bowl and reset the float (flip upside down and make sure the top of the float is level with the top of the bowl)...

Depending on the carb "orientation" hard braking can cause the float to "bob" and let in more gas than needed/ or can cause some fuel slosh (notice in the performance catalogs some carbs come with side hung floats...etc...).


Good luck,

-D.Idiot
Author:  Sam Powell [ Thu Jun 22, 2006 5:45 pm ]
Post subject: 
Forget my first post completely. Sorry, I didn't realize this model carb had the floats that are adjustable while running. That was my mistake. I did not recognize the model number. I have had two Holley carbs of this design in the past, and they did dribble a little fuel when the lock nut was loosened, but not much. What happens when you pull the sight plugs from the side. Does it come squirting out full force, or just dribble a little as it is supposed to do when the floats are just a little too high. It sounds like maybe the floats are set so high, that the bowel is full beyond capacity, thus putting it under pressure that it should not see. Can you turn the adjustment down some and keep it running. The idlel mixture, and high speed circuit for that matter is very dependent on that float being correct. Sorry about the confusion. I read too quickly and was working from the assumption that you have an old Holley one barrel. :oops: :oops:
Author:  skraecken [ Fri Jun 23, 2006 1:54 am ]
Post subject: 
If you have powerbrakes, maybe a vacumleak?
Author:  Sam Powell [ Fri Jun 23, 2006 3:53 am ]
Post subject: 
Someone sells a small container designed to hang under the Holley carb to catch the fuel that drips out when you work on it. It seems like you could make your own catch can so to speak from some kind of pie plate. At the very least you could make a shield that directs the fuel away from the headers and down onto the stearing gear or inner fender.
Sam
Author:  bwhitejr [ Fri Jun 23, 2006 4:07 am ]
Post subject:  Hard Braking - Engine Dies!
Do you have to pull the carburetor or just the bowl to set the float level? This is the technique where you turn it upside down and make the float level with the top of the bowl. :wink:

bwhitejr
Author:  DusterIdiot [ Fri Jun 23, 2006 9:10 am ]
Post subject:  Just the bowl...
Quote:
Do you have to pull the carburetor or just the bowl to set the float level?
You just have to unhook the fuel line, and pull all 4 screws (if new they are hex headed), if brand new you'll need a new bowl gasket as the black one Holley uses on new carbs is like tar paper...(you'll have to pull a low screw first then get a can or cup under there to catch the fuel-about enough to mow my lawn...)


good luck,

-D.Idiot
Author:  AndyZ [ Fri Jun 23, 2006 2:26 pm ]
Post subject: 
Do you have power breaks?
Author:  ValiantBoyWonder [ Sat Jun 24, 2006 12:28 am ]
Post subject: 
i'd suggest a general tune up, check valves especially. my car was running perfectly fine on the highway out to palm springs, and then when i come off the freeway onto the street and stop at the light, dead, and didn't want to turn back on.

adjusted the valves at the hotel that night.

big change.
Author:  Sam Powell [ Sat Jun 24, 2006 5:52 am ]
Post subject: 
If there is enough pressure in the bowel to squirt fuel out the adjustment screw, which is on top, maybe the needles and seats are just not good. Although, on mine, which worked fine, a small amount of fuel seeped out, and I t hink that is normal.
Author:  bwhitejr [ Wed Jun 28, 2006 4:32 am ]
Post subject:  Hard Braking - Engine Dies!
Update - I checked my float levels - they were fine. I checked my fuel pressure (electric fuel pump) it was 4 1/4 lbs. Holley says 5 -7 lbs for the 4160 0-8007 390 cfm. I figure that is not the problem 'cause that would cause problems in fuel delivery at high consumption rates.

So why do my RPMs drop below idle setting when I let off the gas and brake hard?

bwhitejr
Author:  skraecken [ Wed Jun 28, 2006 8:31 am ]
Post subject:  One more time!
If you have powerbrakes, maybe a vacumleak?
Author:  Joshie225 [ Wed Jun 28, 2006 11:01 am ]
Post subject:  Re: Hard Braking - Engine Dies!
Quote:
Update - I checked my float levels - they were fine. I checked my fuel pressure (electric fuel pump) it was 4 1/4 lbs. Holley says 5 -7 lbs for the 4160 0-8007 390 cfm. I figure that is not the problem 'cause that would cause problems in fuel delivery at high consumption rates.

So why do my RPMs drop below idle setting when I let off the gas and brake hard?

bwhitejr
It's fuel slosh. Is your carb mounted with the primaries forward? If so jet extensions and a notched float on the secondary side can help as well as a longer vent tube for the float bowl. The new Holley truck Avengers have a trick bowl vent tube to control slosh. You can connect the two bowl vent tubes with a hose that has holes in it to accomplish the same thing.

http://www.holley.com/data/HolleyNews/P ... 0H-216.jpg

Actually this picture is the new 470 CFM Truck Avenger with annular primary boosters. I doubt it's cheap, but it should make a great carb for a performance slant.
http://www.holley.com/HolleyNews/article.asp?ID=22
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