Technical Holly power valve question..

Holly 4011 spreadbore carb.. 650 (vacuum secondaries)

when at idle, it is dumping fuel from the secondaries...

I quickly tried to adjust the float... but it flooded and I got pissed and took the carb off... to inspect. (I had a blocked squirter on the primary anyway..)

I thought maybe the float was full of gas...
but everything looks good...

except the power valve on the secondary side...

when I blow on it while pushing in the plunger, I can hear air passing through it.... The primary power valve is fine.... air tight.

So, My question is: Will a bad power valve let gas trickle into the chamber... on the secondaries?
Being a vacuum system, I figured that secondary system shouldn't get ANY gas at all until that diaphragm opens up.. ?

sorry if I'm long winded...

 

Check to see if the secondary metering plate is the correct one. My Holley's do not have power valves on the secondary side.

 

No metering blocks on the 4011

different animal.

 

You're half right . A bad power valve will leak into the engine , but you wont be able to see it because it will be from the vacuum port in the base plate below the throttle plates.You have a bad needle and seat or crap stuck in it. Or Possibly a sunken float allowing the bowl to overfill and run out the boosters.Very common , make sure you have a good fuel filter.

 

Yeah I think it's the needle and seat I just put it back together and it's doing the same damn thing

Let me ask a stupid question....

If I only run run one line to the carburetor
To the primary

Will that work temporarily??

No gas going to the secondary line...


Posted by mental telepathy

 

I am fixing to buy a renew kit for it and new needle and seats


Posted by mental telepathy

 

On second thought..
I think I might ditch this quadrajet look alike and buy a New Holly 570 avenger...





Posted by mental telepathy

 

Or, get the renew kit and spend the difference elsewhere? Simple fix, a little "me time" at the bench, the personal satisfaction of knowing it's right vs something full of "imported" components. In my honest opinion, there's only 1 thing that makes a Holley complicated and that's the occasional owner who makes it so. Perhaps one of the easiest performance carburetors ever made. Not slamming you in the least, just sayin...

 

4011 holley is IMO almost a better design that a standard one . other than having to have to take it off to access the PV .

and even if you buy a new one you still have to adjust them a little from UPS kicking them across the dock .

 

Thanks for the kick in the ass

I just ordered the renew kit and a couple clear sight glasses.

Gonna give it a shot.

I really do want to stay with a spread bore rather than try to use adapter plates for a square bore carb


Posted by mental telepathy

 

Only double pumpers have two power valves. You can check those power valves with a mighty vac. Also handy for checking vacuum advance units etc Also make sure you don't have too much fuel pump pressure.

 

Well this ain't a double pumper and it has two power valves...


Posted by mental telepathy

 

its a model 4011 not a model 4175 or 4165 like boltupal was thinking

 

I agree. I have had the 4010 model (square bore version) on a SBC for years. They are as easy to deal with as the old Ford /Autolite 4 barrels. No leaking metering block gaskets to deal with.

 

Yes they will dump fuel if the diaphragm fails and they tend to fail if there is a backfire through the carb. It was always difficult to keep a power valve in one on a dirt track race car but Holley supposedly found a cure for that.

 

Question for you guys familiar with the 4011/4010

Something strange ...
on my 4011 carb, The screw that holds the Primary nozzle assembly has a check ball and a rod (that slips inside the screw)
I can't find ANY diagrams with this type of setup.... they all show 2 solid screws .....
maybe I have a very early 4011??

see #20 in the diagram....

 

Johnt, All of the image diagrams of the 4011 are the same, missing the 4 parts of the accelerator check valve system. The hollow screw, gasket, rod and ball, do not show.
Similar to the 4100 Autolite (I do not know if they interchange).
This reminds me of old maps where a mistake would be carried over to the next map maker.

 

I just put a renew kit in my 4010 and the instruction sheet does not show the check ball,rod either. I just cleaned them up good and replaced the originals with the ball in the bottom. I don't know why the diagrams are like this. The old kits used to provide the parts also. Mine had the ball but the rod and the diagram showing them are missing.

 

Thanks guys
Got it back together and running fine.

This old girl is off to Hemmings soon...



Posted by mental telepathy