Holley Carb Leak?

[dannystarr]

Holley 4053 Carb is leaking fuel out of the secondary shaft on BOTH sides. This is a 780 Vacuum secondary. Carb was just rebuilt 200 miles ago. Car will not start without starting fluid, seems flooded out, then when it starts, the leaks stop. Turn off the car and the leak starts again???. WTF!! WAS running great until this morning. Pulled both bowls and cleaned the needle and seat, no change... Danny   
                                       https://www.youtube.com/watch?v=xRwMvd4wr9U

[cook_dw]

What size power valve was installed in the rear metering block?  By chance is there 2 gaskets under the power valve?  Assuming its a 4519 block.  Make sure the pv is still good also if correct size for your vacuum.

[Kelley W King]

I would check the float site port first. If it is overflowing float or seat problem. If not you have an internal leak. There are ports in the block that bleed to below the  throttle plates. If the get blocked or stopped up the fuel rises and comes out above the plates and leaks out the shaft. If this is it when you shut down the vac no longer draws the fuel down through the plates and it puddles and leaks. Look down the secondary to see if gas is sitting there. usually is it is the float or seat you would have it coming out the vent. Keep you fire extinquisher handy and wear safety glasses.

[Kelley W King]

I tried to find a pic but could not but if you pull the metering block and trace the ports you should see the problem.

[dannystarr]

So it was fine for maybe 25 starts. Fired right up every time no problem. I pulled both bowls and cleaned the needle and seats and set the float levels. I didn't see any obvious dirt in either bowl. Carb was JUST rebuilt, all internal parts are new. Doubt if it's heat exspansion as it does it on start-up, after running for only 30 seconds. So no time to heat up. My last thing to check is to cut in my liquid filled Marshall fuel pressure gauge and see if the regulator has failed. Going to TRY to check the pressure tonight. Will update.. Hoping that is the issue. If not then I will pull the carb plates. I have my extinguisher right by me, it is the one Chick recommended that has much easier clean-up after use. .. Danny

[cook_dw]

I was under the impression this was a rebuild on a new setup.  Check your pv.  If it has failed then it will do what you describe. 

[L78racer]

check the little "o" rings on the needle & seat assemblies. they get hard and brittle and don't seal.
they are a difficult piece to find separately.
best to replace the needle and seat assemblies.
i've got some from this guy and they work great. fast shipping too.
these are correct for 4053 carb.
https://www.ebay.com/itm/163018429248?ViewItem=&vxp=mtr&item=163018429248

[Kelley W King]

I have bought from those guys. They have the odd parts and know what they are talking about. I used to wonder if the carb resto guys really had all the bolts,screws and small parts plated. Look at BPT,s bulk parts and you can see that they just replace them all. If you had several carbs to do the bulk packs are pretty reasonable.

[dannystarr]

Update... Pulled the carb, and took apart. Cleaned the metering blocks with carb cleaner and air. Tested both PV's and they are good. Cleaned the needles and seats. Set the float bowl levels parallel with the bowl body. Reassembled and installed. Fired it up in the garage for 5 seconds, shut it off, STILL leaking in the same spot. New Needle and seat COULD be faulty. So I will change that next. Also will adjust the floats while installed. Was told by the rebuilder that the secondary ball bearing fell out during rebuild and he just left it out. I guess I don't need it?... Danny

[Kelley W King]

You could set it on the bench, add fuel through the secondary vent and look in with a flash light to see where the fuel is coming in. Must be above the throttle plates to cause the leak at the shaft. If the small ports, slots to small holes, in the base plate are blocked it will cause fuel to rise and flow out. It happened to me. It was a hole in gasket that was slightly off but swelled when wet. Do not smoke while doing this.LOL

[BULLITT65]

Update... Pulled the carb, and took apart. Cleaned the metering blocks with carb cleaner and air. Tested both PV's and they are good. Cleaned the needles and seats. Set the float bowl levels parallel with the bowl body. Reassembled and installed. Fired it up in the garage for 5 seconds, shut it off, STILL leaking in the same spot. New Needle and seat COULD be faulty. So I will change that next. Also will adjust the floats while installed. Was told by the rebuilder that the secondary ball bearing fell out during rebuild and he just left it out. I guess I don't need it?... Danny

I am under the assumption that Holley would not have that ball in there if it wasn't necessary. Manufacturers in general only install or assemble what there product needs to operate in the best possible way. If they didn't they could cut more corners.

Businesses that say you don't need something that originally came with you product, usually only say this if they have broken or misplaced an item. If it is more of an optional piece, they give you this option as they rebuilding. I would be skeptical if I heard any part fell out, and they just put to back together without it.

Now I have rebuilt many carbs, and had my fair share of trifles. Haven't had your problem (yet). I assume the secondary throttle plates are adjusted, where you just have a tiny square showing on the inside of the bore of the carb? (secondary slot adjustment)

The other thing I would verify is that all the gasket surfaces are square. I would check the bottom body of the carb, and the base plate with a straight edge, if the is a slight leak, it could be in between those 2 mating surfaces and the gasket, and exiting out the shaft. Also when assembled if it was not torqued down evenly one side could be tighter than the other causing a leak as well.

[RS Copo]

Get new pv gaskets,put a coating of vasoline on them and reinstall carefully.Start the pv,turn the metering block so the pv is pointed down and position the gasket so it is centered on the pv,not up on the ridge. Snug it up firmly, do not go too tight.

[dannystarr]

Update...

50 year old Holley 780 Vacuum Secondary
This problem just started out of the blue. Car was running great. Now does not start without starting fluid. And fuel leaks out of the secondary shaft on both sides ONLY after I turn the engine off.

Cut-in liquid filled Marshall fuel pressure gauge, gauge reads
5.5 at idle. So regulator has NOT failed.
Changed Needle and seat in both bowls
Tested both power valves, they are good. Installed with new gaskets.
Cleaned the metering blocks with carb cleaner and air
Power valves are 6.5, Vacuum at an idle is 11, Close enough for now, I can put 5.5’s in later. Needle stays VERY steady.
 When I slowly rev the engine to 3K the vacuum jumps to 17, when I rack the throttle the vacuum drops to 7. I believe this is normal.
Float bowls fuel level at sight screw BARELY comes over the bottom of the female threads at an idle.
Secondary blades had NO slot clearance showing. I adjusted JUST so the opening was the sum of the width of the rectangular slot. The Primary blades have a Strong 1/8th of an inch showing.
Carb Rebuilder left out a ball bearing in the secondary’s, I remember seeing that pop out on me once. I put it back, as I didn’t even know it was there. THIS carb, does not have that ball. DO I NEED IT? WHAT IS IT?
While engine is running at idle, the inside of the carb is DRY! All blades are dry. When I turn the engine off, fuel begins to drop in from up at the squirters and cover the secondary blades… THEN drip out of the shaft on each side.
WHY do I always get these weird glitches in my carbs?? I am done for the day. Under a house the last two days for 11 hours total!! My back hurts  Danny

[RS Copo]

If fuel is dripping from the boosters,it is usually loose bowl screws.After new gaskets are put in,snug all the bowl screws up after a few heat cycles. Ask the rebuilder where that ball bearing was located.Was it in the bowl above the pump diaphragm?
   It also sounds like your throttle shafts are worn out.

[ZLP955]

As it was only just rebuilt, I would have gone back to the rebuilder to get the issue diagnosed and fixed to your satisfaction; however as you've taken it apart again yourself, very much doubt whoever did it will honour their rebuild warranty. Not that this helps, but was going to suggest you contact the rebuilder......