Shipping cost, delivery date, and order total (including tax) shown at checkout. Amazon has encountered an error. 12-804) is a Low Pressure (1-4 PSI) regulator. I ordered the 12-804 regulator online because I couldn't find one locally, this is for an engine on a piece of equipment that I make my living with. . Somewhat of an inconvenience but that's why it's probably cheaper than other places selling the same part Great product from holley, but these do not come with the supplied tap that's suppose to be in box for the 2 machine screws that mount the regulator to the bracket. NPT Inlet Attachment: This will ensure that the pump will not continue to operate after the engine is . Decrease pressure by turning the adjustment screw counter-clockwise. This is another vexing problem with Ethanol mix, which is about all you can get here in CT. The owner had tried all practical means to reduce the heat gain of the fuel system but with little improvement. There was a problem completing your request. The regulator is a Holley 12-804, I was told it went down to 1 psi and I have a stock mechanical fuel pump. Holley 12-804 Fuel Pressure Regulator - amazon.ca From propelling the LS-, Coyote-, and Gen 3 Hemi-swap trends, to continuously innovating late-model and vintage vehicle performance, Holleys commitment to its customers and their cars is at the core of everything we do. Rich boys replaced their 216 stovebolt 6's with GMC 270 or 302 sixes with a performance "full race" cam. We are sorry. Neither the Holley instructions nor anywhere I can find says what the maximum inlet PSI should be allowed to the regulator - but I was told it was 16 psi and one other spot on the web says something similar. Now my equipment sits idle while I wait for a response from the vendor. . This product is intended only for the thinning of industrial maintenance coatings. We tend to speak of pressure as higher or lower than atmospheric however it is a relative measure and pressure applies under all conditions. I wanted to upload the map, but at 2.73mb, it was too big. Holley Fuel Pressure Regulators 12-803 HLY-12-803. I now think that what was happening was that there was sufficient heat in the carburettor to boil the fuel, the vapor from the boiling increased the pressure above the float preventing it from rising and shutting off the supply. I appreciate it. [{"displayPrice":"$58.17","priceAmount":58.17,"currencySymbol":"$","integerValue":"58","decimalSeparator":".","fractionalValue":"17","symbolPosition":"left","hasSpace":false,"showFractionalPartIfEmpty":true,"offerListingId":"UhTnfcw7IZxaNntXlJwDKCZdMn2swwW9Qa8PxzrWBz%2By8RC0ilxVsHIj8toGUO%2FPmmF8b2HD1iNYooZ7n4ER0XuKiQsQQvJG86lgqsni6KYZs%2FdLcIOIE0Ukulbz%2BJYBuUOC820ciUZxU2UEL9sUjtoq8gdk8bOPIZ3QChg8zpgyIZxlTaXQEA%3D%3D","locale":"en-US","buyingOptionType":"NEW"}]. In some areas, according to the map, RVP can vary from about 7.0 to 9.0 in some of the fuels. My bypass line has a shut-off valve that I can use to manually adjust the pressure, but when air bubbles develop within the input fuel line, this valve requires adjustment to maintain the fuel pressure. Never had it act up while running, but since E10 fuel came along it is borderline getting started after hot shutdowns. . on this design the adjusting screw all the way out should decrease the pressure the most - IF the ball valve will seat TIGHT, When I adjusted pressure below 30 - it would not seat any longer even with the adjustment screw all the way out. Holley 12-803 Holley Fuel Pressure Regulators | Summit Racing The issue is boiling points UNDER PRESSURE we are talking about here - though the BP article speaks to other issues of engine and carburetor design contributing to the vapor lock problem. fuel pressure problem - holley blue pump & reg | Hot Rod Forum ***The inlet pressure limitation is 7 psi. Holley 804 fuel pressure regulator install - YouTube The only difference that the Holley tech told me between the two springs is the color. They put everything they could into the coal oil including what we would consider low grade gasoline. Holley 804 fuel pressure regulator install - YouTube 0:00 / 5:58 Holley 804 fuel pressure regulator install Schnebs Garage 2.42K subscribers Join Subscribe 72 Share Save 15K views 3 years ago. I found this document on my local Oil Refinery's web site and it may help explain some of the problems with vapor lock and hard start. Some can be used for either - or. [endif]-->. Much of the excess engine heat will end up soaking the fuel system under the hood. Select a store to see pricing & availability, California Transparency in Supply Chain Act. The point being here - you need enough steady high enough pressure on the ball to allow it to regulate down reliably too. The other possibility is that it is due to the higher pump pressure. [endif]-->