Holley 4 barrel without power valve. How much is it hurting my gas consumption.

[smassey22180]

Recently I picked up a cheap used intake and 4 barrel carb (4.3 GS from around 1998) to replace my current questionable 2 barrel. The carb is a Holley 4160 model 80487. This is a marine carb that does not come with a power valve from the factory. After talking to several carb people, all seem to agree that this is an older design and gas mileage will be affected. Since there is no PV, it has bigger jets to compensate which are "on" all the time. A PV only adds fuel as needed.

My question is how bad is the fuel consumption? I am leaning towards a new carb for reliability alone but bad fuel consumption would push me over the edge. This is what I would get. https://holley.com/products/fuel_sy..._carburetors/marine_carburetors/parts/0-80492

Another option is to rebuild and run it for a season to see what consumption I get. A rebuilt carb that comes off a running engine is more valuable for resale anyway.

thanks

 

[gm280]

Is the power valve missing and therefore a power valve block installed? Because if there is a hole for the power valve and no block installed, that is going to drink fuel faster then you can fill the tank. In fact I really don't think the carb would even work without a block installed. It would probably flood or run extremely rich if at all. You can do a few things, but I'd talk to some boating engine experts first to get their knowledge about what size to buy and install. You can either get their suggestion or pick one in the usual range and work from there. If you buy a PV, and they really are not that expensive, and install it and try it out! Then you can resize the jets also. And again the jets are not expensive either. So a little tuning on your part you could yield yourself with a good running Holly carb. But you have to really understand PV's to make qualified decisions about what you want from the carb. Holly carbs as so adjustable that it can work with a knowledge of how to tune it for your needs.

 

[smassey22180]

The metering block is actually closed off where the PV goes. There is no hole or threads. I talked to Holley tech support today. From what they say, I can't simply replace the metering block and jets as there are other parts of the carb that are affected.

 

[wrench 3]

I think that the idear behind that carb was that in the marine application it's always running under power, never coasting. So a system to switch between power and coast was redundant.
With that line of thinking, your fuel consumption shouldn't change all that much.

 

[K-2]

No PV on the primary side?
I'm curious about this, my cousin has this carb on his jet boat.

 

[smassey22180]

It has a PV on the primary side?
No PV on the secondary side?

No PV on the primary side. Secondary side is just a metering plate without a block which is normal for all versions of this carb.

thanks

 

[Scott Danforth]

VP spec'd Holley Carb's came without power valves in many instances.

from my racin' buds, if you run a power valve delete kit, you need to run 6 numbers richer on the primary jets