VP 4.3GS Carb Tuning Vacuum Port?

[valleyviewlawns]

Nope, threaded brass plug unless someone installed that aftermarket clear plastic plugs ( not marine approved)

 

[Scott Danforth]

This are not externally adjustable

You can remove the bowls without pulling the carb if you need.

 

[valleyviewlawns]

This are not externally adjustable

You can remove the bowls without pulling the carb if you need.

I did.

I ran it on the muffs this evening to get the timing adjusted and adjust the carb, but it won't idle. Fouled the plugs again.

 

[Lou C]

Are you sure that the needle valves are holding & cutting off fuel flow when they should?

 

[dubs283]

What setting are the idle/air screws set to?

Spec is around 3/4 turn out from seated then adjust accordingly. I've never had a properly tuned holley on a sound engine at more than one turn out from seated

 

[Scott Danforth]

If the float is too high, fuel gets pushed thru the boosters

As Lou asked, are the floats cutting off flow?

 

[valleyviewlawns]

Are you sure that the needle valves are holding & cutting off fuel flow when they should?

I'm not sure how to check that. I put new needles and seats in it. Floats are adjusted to spec.

 

[valleyviewlawns]

What setting are the idle/air screws set to?

Spec is around 3/4 turn out from seated then adjust accordingly. I've never had a properly tuned holley on a sound engine at more than one turn out from seated

Screws are out 3/4 turn.

 

[valleyviewlawns]

If the float is too high, fuel gets pushed thru the boosters

As Lou asked, are the floats cutting off flow?

When I put the new needles and seats in it, I flipped the bowls over and set them so they're level with the top of the bowl. Not resting on the bowl, level with it.

 

[Lou C]

An easy way to tell is to remove the carb drain the fuel out & see if you can blow thru the inlet with the carb flipped upside down. If you can the needles aren’t holding.

 

[valleyviewlawns]

An easy way to tell is to remove the carb drain the fuel out & see if you can blow thru the inlet with the carb flipped upside down. If you can the needles aren’t holding.

Set like this. Both primary and secondary.

 

[valleyviewlawns]

An easy way to tell is to remove the carb drain the fuel out & see if you can blow thru the inlet with the carb flipped upside down. If you can the needles aren’t holding.

Is there a certain PSI to use?

 

[Lou C]

No particular pressure you just shouldn’t be able to blow thru it

 

[dubs283]

Can you see fuel dribbling down the venturi clusters at idle/near idle speed?

Is the ignition timing and firing order correct?

Is the engine itself mechanically sound?

What brand/style rebuild kit did you install?

 

[Bondo]

Is there a certain PSI to use?

Ayuh,..... Carb fuel pumps usually run 4 to 6 psi,.....

 

[valleyviewlawns]

Can you see fuel dribbling down the venturi clusters at idle/near idle speed?

Is the ignition timing and firing order correct?

Is the engine itself mechanically sound?

What brand/style rebuild kit did you install?

I do not see fuel dribbling down the Venturi clusters at idle. The ignition timing and the firing order is confirmed and correct. I will do a compression test this evening. I used the Holley trick kit that Holley technical support sent me.

 

[valleyviewlawns]

Ayuh,..... Carb fuel pumps usually run 4 to 6 psi,.....

When I put the fuel pressure gauge after the fuel pump, I was getting 7 PSI when trying to start the engine.

 

[Scott Danforth]

When I put the fuel pressure gauge after the fuel pump, I was getting 7 PSI when trying to start the engine.

That may push your needles open

 

[Lou C]

Wanna laugh I had the EXACT SAME PROBLEM with a brand new 4160 specified for the V6. Rich running no matter what I did. Called their tech line tried everything. In disgust I pulled the 30 year old QJet out of the garage that I thought was too old to rebuild. Took my time to really clean it & checked all the passages. Bolted it on and, like magic ran perfect. About 6 months later got curious & took that infernal Holley all apart. What I found was that the clutch bolts on the secondary metering plate were loose. This may have allowed more fuel flow from the secondary system causing the fuel mix to be too rich. The Holley is designed to flow some fuel from the secondary system to keep the fuel in the rear bowl from going bad. Anyway I left the QJet on it since then & still running fine. The Holley still sits in the box on a shelf in my garage. So check that if you haven’t!
Not sure what I’m gonna do with it but I like spare parts. Honestly while Holleys are super easy to get parts for I don’t think their quality control is all that great.

 

[valleyviewlawns]

Wanna laugh I had the EXACT SAME PROBLEM with a brand new 4160 specified for the V6. Rich running no matter what I did. Called their tech line tried everything. In disgust I pulled the 30 year old QJet out of the garage that I thought was too old to rebuild. Took my time to really clean it & checked all the passages. Bolted it on and, like magic ran perfect. About 6 months later got curious & took that infernal Holley all apart. What I found was that the clutch bolts on the secondary metering plate were loose. This may have allowed more fuel flow from the secondary system causing the fuel mix to be too rich. The Holley is designed to flow some fuel from the secondary system to keep the fuel in the rear bowl from going bad. Anyway I left the QJet on it since then & still running fine. The Holley still sits in the box on a shelf in my garage. So check that if you haven’t!
Not sure what I’m gonna do with it but I like spare parts. Honestly while Holleys are super easy to get parts for I don’t think their quality control is all that great.

When I had the Holley off the engine and flipped over on my workbench, I noticed that there is about 3/16" play on the secondaries between closed and sitting on the adjustment. I was trying to set the transfer slots. I set it so when they were open, there is only about .020" reveal on the transfer slot, and none when it is fully closed.