Do power valves effect idle?
The idea behind having a power valve that is open at idle is that the the idle and power enrichment circuits are separate and therefore, there will be no effect. While the idle and main circuits are separate, an over-rich main circuit at idle will have an effect on idle quality.
What does a power valve plug do?
Product Description. This plug is used to block the power valve circuit and fits carburetors with 1/2″ x 28″ threads.
Can a power valve cause flooding?
An open power valve, due to improper selection or rating, will flood the engine at idle… The Holley PV, like other carb power enrichment systems, feeds additional fuel into the main discharge passages. These main passages discharge their fuel through the main discharge nozzles in the booster venturies of the carb.
What happens if my power valve is too small?
The incorrect size power valve, or a blown out power valve can cause problems such as poor fuel economy, black smoke emanating from your exhaust, dark or fouling spark plugs and a poor idle.
What happens when a power valve goes bad in a carburetor?
If you have a 94 type carb, a bad power valve would cause a rough idle (too rich) and rich when cruising at steady throttle. Also a drop in fuel mileage. The way you describe your engine running, it isn’t a bad power valve (if a 94 type carb).
Do I need a power valve?
The function of a power valve is to enable the vehicle to have proper fuel mixture at idle and low to mid throttle operation. If your engine has a large cam, very little vacuum at idle and low speed, and/or you leave the line at high RPM, then you won’t need the power valve.
Will a bad power valve cause rough idle?
What happens if you don’t have a power valve on an engine?
Since the power valve is for fuel enrichment, if it is missing, the engine needs to get the extra, required fuel from somewhere. So, If you decide to do away with the power valve, you must increase the main jet sizes considerably (typically 6 – 10 jet sizes). Knowing what power valve you have is as easy as reading numbers.
How do you choose the lowest power valve?
If your divided number falls on an even number, you should select he next lowest power valve number. For example, a vacuum reading of 8-inches, divided by two and you come up with a number of four.
What power valve do I need for my carburetor?
The divided number will determine the correct power valve that you need. As an example, a vacuum reading at idle of 13-inches needs to be divided by two, which results in a number of 6.5. Therefore, you should have a number 65 Holley power valve installed in the carburetor.
What do the numbers on a power valve mean?
Each power valve is stamped with a number that indicates the correct vacuum opening point. For example, a power valve with the number 65 stamped on it will open at 6.5 inches of engine vacuum. Many racers will instinctively remove the power valve and install a plug in its place.