Holley 650 dp problem

[440marv]

my 650 dp is getting fuel in the full vacuum port on the front of carb. Any help would be greatly appreciated.

 

[mopowers]

How much fuel?

Some of the new proform carbs and others have the vacuum port in a spot that seems to collect a small amount of residual fuel. If it's running well, I wouldn't worry about it.

 

[440marv]

How much fuel?

Some of the new proform carbs and others have the vacuum port in a spot that seems to collect a small amount of residual fuel. If it's running well, I wouldn't worry about it.

It fills the vacuum cap full and the car runs ruff like its flooding. I have checked the floats and there good.

 

[mopowers]

How far out are the idle mixture screws?

 

[AJ/FormS]

Are you talking about the PCV port?
If you are, then you need to hook it up,properly,else the butterflies will be too far open messing up the T-port sync.Then you will have a dickens of a time leaning it out.
What's under it for an engine and cam?

 

[440marv]

How far out are the idle mixture screws?

2 turns out

 

[440marv]

Are you talking about the PCV port?
If you are, then you need to hook it up,properly,else the butterflies will be too far open messing up the T-port sync.Then you will have a dickens of a time leaning it out.
What's under it for an engine and cam?

No it's the small full vacuum port. The motor is a 360 with a mp 528 solid cam.

 

[AJ/FormS]

Well then what's your idle timing at?And idle RPM with the PCV working.
On a Holley, the mixture screws should be closer to 1 turn out. Ima guessing the throttle is a hair too far closed and so the transfers are not contributing enough fuel, so the mixture screws had to be increased. But with more butterfly opening, the idle speed will go up. And the only way to get it back down is to retard the timing.
Then you may find the engine wanting more air. So then to solve that the fix is often to crack the secondaries. But if they're dry, as in no 4-corner idle, then my experience has been that the engine runs a hair lean on the back cylinders,idles rough,and it creates an awful,singe your nosehairs,stink in the exhaust. So the usual workaround is to close up the secondaries and drill little holes in the primary butterflies, on the transfer port side, but not too close to the T-ports, about 1/4 inch away. This will smooth her idle out. Try 3/32s, 1 in each blade. Drill from the bottom and lightly chamfer both sides. Then dink around with the pumps and dry the primary up as much as you can without creating driveability issues.
This is called syncing up the T-ports. You can read all about it on the Holley website.
I don't know if this will eliminate the liquid fuel in that cap, but it's a step in the right direction. I had an MP292/108 for a while in my 367. I can't recall if it ever really dried up. The .528solid cam IIRC is a 284/112. Are you running it on an airgap? They run pretty cool. I think that port just accumulates fuel cuz it's a vacuum accumulator and the plastic cap is a flexible "diaphragm" on one end acting like a pump, to suck the fuel in.. Have you checked the plug colors?

Btw; you know that cam wants more carb, right? And a DP if a stick-car. But the 650 is doing ok below 6000. That cam power-peaks at somewhere close to 5500 depending on the heads. With an automatic it will want the 1-2shift to be about 1000 rpm higher, and the 2-3 about 800 higher, and the trap at about 300/400 higher.So when you get on it, say at the track, a 750 will be the hot ticket. But 650s are hot on the street.

 

[440marv]

Well then what's your idle timing at?And idle RPM with the PCV working.
On a Holley, the mixture screws should be closer to 1 turn out. Ima guessing the throttle is a hair too far closed and so the transfers are not contributing enough fuel, so the mixture screws had to be increased. But with more butterfly opening, the idle speed will go up. And the only way to get it back down is to retard the timing.
Then you may find the engine wanting more air. So then to solve that the fix is often to crack the secondaries. But if they're dry, as in no 4-corner idle, then my experience has been that the engine runs a hair lean on the back cylinders,idles rough,and it creates an awful,singe your nosehairs,stink in the exhaust. So the usual workaround is to close up the secondaries and drill little holes in the primary butterflies, on the transfer port side, but not too close to the T-ports, about 1/4 inch away. This will smooth her idle out. Try 3/32s, 1 in each blade. Drill from the bottom and lightly chamfer both sides. Then dink around with the pumps and dry the primary up as much as you can without creating driveability issues.
This is called syncing up the T-ports. You can read all about it on the Holley website.
I don't know if this will eliminate the liquid fuel in that cap, but it's a step in the right direction. I had an MP292/108 for a while in my 367. I can't recall if it ever really dried up. The .528solid cam IIRC is a 284/112. Are you running it on an airgap? They run pretty cool. I think that port just accumulates fuel cuz it's a vacuum accumulator and the plastic cap is a flexible "diaphragm" on one end acting like a pump, to suck the fuel in.. Have you checked the plug colors?

Btw; you know that cam wants more carb, right? And a DP if a stick-car. But the 650 is doing ok below 6000. That cam power-peaks at somewhere close to 5500 depending on the heads. With an automatic it will want the 1-2shift to be about 1000 rpm higher, and the 2-3 about 800 higher, and the trap at about 300/400 higher.So when you get on it, say at the track, a 750 will be the hot ticket. But 650s are hot on the street.

Thanks for the help turned the idle up and brought the timing down from 18deg to 16deg and so for so good.