VP 4.3GS Carb Tuning Vacuum Port?

[valleyviewlawns]

All 3 plugs on port side bank were fouled this time, soot covered. Starboard side plugs were just a little wet with fuel. Fuel pressure is 6psi at the regulator. Going to pull the carb again and take a look at everything.

1. 146
3. 146
5. 152
2. 146
4. 146
6. 150
Compression test boat, 7/8/2023

That may push your needles open

I got a question here. I have slack in my secondary linkage. And when I went to replace the diaphragm in the secondary, the one that I pulled out of the carb is a short one, but there is a short and a long in the kit. Do you think the long would take up that slack? I'm wondering if that slack is from having the wrong diaphragm in the carb? When I was trying to set the transfer slots in the secondaries, the throttle plates moved quite a bit, like there is slack in the linkage.

 

[Scott Danforth]

Diaphragm pulls against the spring.

Do you have the correct spring

 

[valleyviewlawns]

Diaphragm pulls against the spring.

Do you have the correct spring

Spring is red. Holley spec on this carb is red, carb number R75007-1

I am also seeing this defect in the mating surface. Should I clean this up?

 

[valleyviewlawns]

Diaphragm pulls against the spring.

Do you have the correct spring

I guess another question I could ask is how do I determine if this carb is spec's for this engine?

 

[dubs283]

I guess another question I could ask is how do I determine if this carb is spec's for this engine?

By the jets?

Is this the original carburetor rebuilt or a different one?

 

[valleyviewlawns]

By the jets?

Is this the original carburetor rebuilt or a different one?

I bought the boat used this spring. PO put a new engine in it 2 years ago. Used it once and parked it. I have no idea if this carb is original to the boat. VP says their number, for my engine serial number and spec number, is 3858333. How would I find the specs for that carb? I'm not sure where to find which jets, springs, etc is spec for my 4.3GS engine.

 

[dubs283]

How would I find the specs for that carb?

In the appropriate oem service manual based on serial/model number/year

 

[valleyviewlawns]

In the appropriate oem service manual based on serial/model number/year

When I try to go through the VP store the manuals page has been erroring out for the last 6-8 weeks. If I give you my serial/model/year, can you point to a place I can purchase one?

 

[valleyviewlawns]

That may push your needles open

Holley tech said these are good up to 7.5psi.

 

[dubs283]

If I give you my serial/model/year, can you point to a place I can purchase one?

Have you tried the google volvo penta store?

It's quite handy and available to the public

 

[Scott Danforth]

For Holley carbs, forget the middleman

Holley

Holley is home to the top automotive performance brands including Flowmaster exhaust, MSD Ignition, Holley EFI, Hurst Shifters, Accel plug wires, Hooker Headers and many more.

documents.holley.com

Holley
https://documents.holley.com › ...PDF
Holley Carburetor Numerical Listing

 

[valleyviewlawns]

Have you tried the google volvo penta store?

It's quite handy and available to the public

Yes sir. When I get to the manual download section for my serial number it errors out. I've been trying for 6-8 weeks.

 

[valleyviewlawns]

For Holley carbs, forget the middleman

Holley

Holley is home to the top automotive performance brands including Flowmaster exhaust, MSD Ignition, Holley EFI, Hurst Shifters, Accel plug wires, Hooker Headers and many more.

documents.holley.com

Holley
https://documents.holley.com › ...PDF
Holley Carburetor Numerical Listing

I have this. I just can't tell if this is the carb spec'd to my engine.

 

[valleyviewlawns]

Have you tried the google volvo penta store?

It's quite handy and available to the public

Here is the link with my serial number in it. I have tried it on my laptop and my phone. And on 3 different browsers. Weirdest thing I have seen in a while.

Manual And Specification

productcenter.volvopenta.com

 

[Scott Danforth]

I have this. I just can't tell if this is the carb spec'd to my engine.

4.3 gets a 600 or 650cfm if it's a 4-barrel. Or 500 CFM if it's a 2-barrel

 

[valleyviewlawns]

Thank you sir. I figured out why my secondaries wouldn't close all the way. Got that fixed. Are the secondary transfer slots supposed to be exposed at idle, or just the primary transfer slots?

4.3 gets a 600 or 650cfm if it's a 4-barrel. Or 500 CFM if it's a 2-barrel.

 

[Scott Danforth]

Primary

 

[valleyviewlawns]

Rich running is common on Holley carbs, one of the causes is that the throttle blades at idle are too far open, exposing too much of the idle transfer slot. That slot should be a square shape, as seen from below the primary throttle valves. At idle you want it pulling fuel only from the idle system.
A blown power valve can also cause that, although I know that the 4160 Holley carb originally used by OMC & Volvo on the 4.3 does not have a power valve. Not sure if you have that same exact model #.
I don't think a V/P 4.3 should have 18* of advance at 600 rpm!
My old OMC gets set at 6*BTDC, full centrifugal advance at 3200 rpm is 12*, for a total timing advance of 18*. Yes much lower than the V8s, not sure why but that's how it is.

Holley 0-80492 600 CFM Marine Carburetor-Aluminum

All Holley Marine Carburetors are designed to meet Coast Guard specifications. A marine carburetors fuel metering system is calibrated to compensate for unique engine loads found on boats. The J-style vent tubes direct fuel/fumes back into the carburetor for safe operation while on rough...

www.holley.com

this is the carb used on the OMC and V/P 4.3s. No power valve.

Is there a fix for this? This is on the primary transfer slots. One is open more than the other.

 

[valleyviewlawns]

Primary

Thank you.

 

[dubs283]

Is there a fix for this?

knipex