Leaking Holley carb. [Archive] - Team Camaro Tech

: Leaking Holley carb.


jjgrizz73
Feb 19th, 12, 01:04 PM
Hey everyone, I decided to finally try and figure out this holley carb problem again. I bought the carb used/rebuilt and had problems with leaking venturis. I bought another rebuild kit thinking it was the power valve or something else, it wasnt. I cleaned the whole thing out and it still leaked and wouldn't let the engine idle. Anyone have ideas? I'm thinking it could be a warped base plate because it does seemed warped but not sure if it would cause this issue. It is not the floats I played with them for hours and they are set perfectly. Fuel pressure was also set. I have an edelbrock on there now, but I'd like to get this holley working properly.

Thanks

Steptoe
Feb 19th, 12, 07:10 PM
Anyone have ideas? I'm thinking it could be a warped base plate because it does seemed warped but not sure if it would cause this issue

OK think about it, the carb gets bolted to the base plate...then the warped base plate gets bolted to the valley cover...and gets bent...what happens then to the stuff already bolted to the base plate.
Holley, well most carb manufactures make a big deal about toquing down carbs correctly, and not just because of possible manifold vaccuum leaks.

frankk
Feb 19th, 12, 08:08 PM
You say the venturies are leaking. Is there raw fuel leaking out of the venturies? If so you have float problems possibly stuck, seat not sealing or hole in float.

camaro_fever68
Feb 19th, 12, 08:21 PM
Pull the little brass screws on side of the bowls and see if the fuel level is correct. You want the level set right to the bottom of the hole.

Another thing to check is the gasket between the main body and baseplate. Most carb kits come with 3 different base gaskets for 600, 650-800, and 850 CFM carbs. If the right gasket was not used it will cause the boosters to leak fuel and kill the engine.

Never seen a warped baseplate cause fuel to pour out, mostly vacuum leaks.

Straight-line-69
Feb 19th, 12, 08:29 PM
If you see fuel leaking with the engine running, look for somthing around the fuel bowl; accelerator pumps are a likely source.

jjgrizz73
Feb 20th, 12, 04:48 AM
Yes there is raw fuel leaking out of them. I changed the needle valves and set the floats correctly but I guess there can be a problem with them sealing correctly. I never took the main body off the base plate, I can do that. What would I be able to do to eliminate the possible accelerator pump issue?

Straight-line-69
Feb 20th, 12, 11:42 AM
What would I be able to do to eliminate the possible accelerator pump issue?

Remove the carb from the engine and replace the little pump diaphram. Easy,..four little screws. Not sure which Holley you have but this is probably what you need:

http://www.summitracing.com/parts/HLY-135-5/

Steptoe
Feb 20th, 12, 12:26 PM
Never seen a warped baseplate cause fuel to pour out, mostly vacuum leaks.

I'm thinking it could be a warped base plate because it does seemed warped but not sure if it would cause this issue.
If it "seems" warped without actually checking, and it is, the chances are it is going to be damn warped...and if it has been warped that far the question arises what else in this 2nd had carb has had the crapper screwed out of it, twisted warped over torqued, bits of wire jambed down in places should never have been, drilled out etc etc.

And yes we have seen 1 carb over the yrs that was so warped it leacked, wouldnt seal or even jet up right.
2nd hand carbs that MAY need a rebuild always causes problems and end up costing more money more headackes than simily dialing a the corect carb out of the box.
Just go thru the threads here alone with 2nd hand carbs and issues.

jjgrizz73
Feb 20th, 12, 03:46 PM
I checked the base to see if it was warped its not visible by just looking at it.

Steptoe
Feb 20th, 12, 06:59 PM
cant check by just looking....use a known straight edge, check both sides of the base plate and the manifold.
Take extra care looking at the mounting cnrs are not 'bent'

Straight-line-69
Feb 20th, 12, 07:16 PM
Warped baseplate? As stated above, that would cause a vacuum leak but not a fuel leak. Again, if she's dripping with engine running, look around the fuel bowls.

rszmjt
Feb 20th, 12, 07:58 PM
Jeff - What is the list number of the carb, and does it have centre pivit floats or side pivit floats. Does it have the Brass floats or the nitrophyl (black) or the duracon (white plastic). Also is the fuel coming out the front boosters or the rear secondaries?. How much fuel pressure do you have? How big is the engine, and how much camshaft? Need more info to try to figure this out.

Take the carb off and turn it over, are the throttle blades about 1/4 to half way up the idle transfer slots? If they are a bunch higher it is probably pulling the fuel out of the boosters, which is normal with too open a throttle blade.

Post all this info Please.

Everett#2390
Feb 21st, 12, 03:31 AM
Yes there is raw fuel leaking out of them. I changed the needle valves and set the floats correctly but I guess there can be a problem with them sealing correctly.If fuel is leaking/dribbling from the venturis while idling on level ground, I would think the fuel level is set alittle too high.

jjgrizz73
Feb 21st, 12, 12:30 PM
Jeff - What is the list number of the carb, and does it have centre pivit floats or side pivit floats. Does it have the Brass floats or the nitrophyl (black) or the duracon (white plastic). Also is the fuel coming out the front boosters or the rear secondaries?. How much fuel pressure do you have? How big is the engine, and how much camshaft? Need more info to try to figure this out.

Take the carb off and turn it over, are the throttle blades about 1/4 to half way up the idle transfer slots? If they are a bunch higher it is probably pulling the fuel out of the boosters, which is normal with too open a throttle blade.

Post all this info Please.

Here are some pictures...The base plate is NOT warped, I checked it today again. Im not sure of the list because the choke was milled off. Center pivot floats(brass). I believe the fuel was coming out of the secondaries, its been a long time though. Fuel pressure was at 5.5-6psi. Motor is a 461 with these cam specs:


Advertised Duration (Int/Exh): 268/276
Duration @ .050 (Int/Exh): 227/233
Gross Valve Lift (Int/Exh): .542/.554

http://i182.photobucket.com/albums/x198/jjgrizz73/IMG_9290.jpg
http://i182.photobucket.com/albums/x198/jjgrizz73/IMG_7328.jpg
http://i182.photobucket.com/albums/x198/jjgrizz73/IMG_6780.jpg
http://i182.photobucket.com/albums/x198/jjgrizz73/IMG_5641.jpg
http://i182.photobucket.com/albums/x198/jjgrizz73/IMG_4102.jpg

Steptoe
Feb 21st, 12, 04:29 PM
The base plate is NOT warped, I checked it today again
Good.. then it is either
crap in the inlet bowl valves..they/it is not closing off...or mis matched damages seats.
Float level(s) not set correct...drop the fuel levels down, fire up, pull the sight scews, shake the car side to side.. the fuel should just slop out the hole.
And u will know when the secon butterflies are nor adjusted correct...the idle and mixture screws will not be in the factory 1 1/2 turns out... adjust secondaries on the car with engine running.... a bent rivet with 1 end flatened to fit up under the edge and use as a screw driver....no not have the butterflies sitting on the bores...fully closed..caused binding and damage.

rszmjt
Feb 21st, 12, 06:29 PM
Check to make sure the float is not bent, compare it to the front float or a known good original. I have seen them get bent before if someone used compressed air to blow off the carb after cleaning. That makes the float seem like it is adjusted correctly but it does not close off the needle and seat at the correct ratio rate.
For that matter floats are cheap, maybe just replace it if in doubt. -

http://www.summitracing.com/parts/HLY-116-2/