poncho.loco Posted November 27, 2021 Share Posted November 27, 2021 Brand new Poncho Loco thread for a brand new issue... Poncho runs and all, but he runs rich & rough, and we spotted fuel coming out the vent tube into the throat of the carb. We determined that the fuel pressure was too high, so we gave the Holley 12-803, Shiny Fuel Pressure Regulator 4.5-9 Psi a try, despite seeing comments on Amazon that it did not work at all for some buyers. Well, it didn't work at all for us either. We turned the adjustment screw all the way to either extreme while the truck was running, and the fuel pressure remains unchanged. It our case it stayed at exactly 6psi, which is just enough to overpower the Holley carb's new float valve. We need 5psi. So I can't recommend this regulator as of now. Amazon is sending us a new one and we'll try it. Meanwhile, it's back here to the forum to search for others who have solved this issue with another device. Has anyone BTDT with too much fuel pressure on a Holley 2300 carb? The needle and seat are new, its bore is clean, and the assembly has no visible defects. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 27, 2021 Share Posted November 27, 2021 I've used two of those regulators with no problems. One was on Dad's truck when I had Rusty's engine in it, and it was feeding an Edelbrock 1406. And I'm currently running one on Big Blue, but it is in series with with a return-style regulator in front of it as I'm running EFI pumps and need to drop the pressure down a bunch for an Eddy carb. No experience with the Holley 2500. But, too much fuel pressure doesn't usually give a high idle. In fact, just the opposite. Usually a high idle is due to a vacuum leak. Link to comment Share on other sites More sharing options...
poncho.loco Posted November 27, 2021 Author Share Posted November 27, 2021 I've used two of those regulators with no problems. One was on Dad's truck when I had Rusty's engine in it, and it was feeding an Edelbrock 1406. And I'm currently running one on Big Blue, but it is in series with with a return-style regulator in front of it as I'm running EFI pumps and need to drop the pressure down a bunch for an Eddy carb. No experience with the Holley 2500. But, too much fuel pressure doesn't usually give a high idle. In fact, just the opposite. Usually a high idle is due to a vacuum leak. Note: I edited the first post (it's a Holley 2300 carb, not 2500, and there is no high idle issue). Sorry about that! Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 27, 2021 Share Posted November 27, 2021 Note: I edited the first post (it's a Holley 2300 carb, not 2500, and there is no high idle issue). Sorry about that! Ok. Still no experience with that carb. However, it is a Holley and rich conditions are normal with a blown power valve. That will do about the same as too much fuel pressure. And Holley's are supposed to handle more than 6 psi. It is Edelbrocks or Carters that don't like that much pressure. Link to comment Share on other sites More sharing options...
mat in tn Posted November 27, 2021 Share Posted November 27, 2021 is the fuel over running into the carb venturis? most holley two bbl are center hung float design and are easily adjusted too high. keep in mind that high is relative to the incoming fuel pressure and often its necessary to set them a little lower. most holleys can manage 6 to 7 lbs of pressure well. Link to comment Share on other sites More sharing options...
FuzzFace2 Posted November 27, 2021 Share Posted November 27, 2021 is the fuel over running into the carb venturis? most holley two bbl are center hung float design and are easily adjusted too high. keep in mind that high is relative to the incoming fuel pressure and often its necessary to set them a little lower. most holleys can manage 6 to 7 lbs of pressure well. I have never had any issues with any Holley carb of to much psi as they handle it pretty good. I would check the float level as I bet it is set to high. I have run a few of the 2300 carbs with no issues. I have also used the Holley regulators with the blue pumps with no issues. Dave ---- Link to comment Share on other sites More sharing options...
85lebaront2 Posted November 27, 2021 Share Posted November 27, 2021 Ok. Still no experience with that carb. However, it is a Holley and rich conditions are normal with a blown power valve. That will do about the same as too much fuel pressure. And Holley's are supposed to handle more than 6 psi. It is Edelbrocks or Carters that don't like that much pressure. Considering that the fuel pressure spec on the 460 hot fuel handling package is 9 psi. a Holley should handle that with no problems. I had a Carter high performance vane pump feeding a Holley Racing mechanical pump on my 1966 Shelby. The Holley would draw through the Carter pump under normal driving, the Carter pump was in the rear next to the tank and was used to push extra volume through the 5/16" fuel line. All this was to feed two Holley four barrels and I never had a flooding issue. Link to comment Share on other sites More sharing options...
poncho.loco Posted December 7, 2021 Author Share Posted December 7, 2021 Considering that the fuel pressure spec on the 460 hot fuel handling package is 9 psi. a Holley should handle that with no problems. I had a Carter high performance vane pump feeding a Holley Racing mechanical pump on my 1966 Shelby. The Holley would draw through the Carter pump under normal driving, the Carter pump was in the rear next to the tank and was used to push extra volume through the 5/16" fuel line. All this was to feed two Holley four barrels and I never had a flooding issue. Thanks to everyone for the replies. The replacement regulator didn't work either, but we did spot an overlooked vacuum leak (thanks for that info Gary) and adjusted the float. And just like that, the idle went from 3 thousand to 15 hundred rpm, and fuel stopped spurting out of the float vent. Pressure was last measured at 5 psi, which seems to be just fine. Link to comment Share on other sites More sharing options...
poncho.loco Posted December 7, 2021 Author Share Posted December 7, 2021 Thanks to everyone for the replies. The replacement regulator didn't work either, but we did spot an overlooked vacuum leak (thanks for that info Gary) and adjusted the float. And just like that, the idle went from 3 thousand to 15 hundred rpm, and fuel stopped spurting out of the float vent. Pressure was last measured at 5 psi, which seems to be just fine. Now to a minor issue we've run into today... We noticed a loose bolt on the alternator bolting that seems too thin as we can just push it in the hole. Diameter of the shank measured was .348 in. I should have measured the major diameter of the threads but we believed it's a 3/8" bolt. Does anyone know what diameter bolt should be in its place, and if so where to find one? Alternatively, the threads may be entirely stripped out and we do have the right bolt. Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 7, 2021 Share Posted December 7, 2021 Now to a minor issue we've run into today... We noticed a loose bolt on the alternator bolting that seems too thin as we can just push it in the hole. Diameter of the shank measured was .348 in. I should have measured the major diameter of the threads but we believed it's a 3/8" bolt. Does anyone know what diameter bolt should be in its place, and if so where to find one? Alternatively, the threads may be entirely stripped out and we do have the right bolt. Glad you got that first problem solved. As for the alternator, that bolt goes into the head. There shouldn't be threads in the bracket. Link to comment Share on other sites More sharing options...
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