Results 1 to 5 of 5

Thread: Losing Faith

  1. #1

    Default Losing Faith

    I've been trying to get this HR-580-VS carb to work for four months (LINK & LINK). I bought it secondhand, but it looked brand new. I just can't get it to work. First the float level was going up & down. Then the front float was flooding. Then the pressure was going up & down, which doesn't sound like a carb issue, but never happened before. Now the rear bowl is flooding and I was never able to get the off idle stumble out of it completely. I followed the advice from Holley step-by-step to set floats, I put the fuel pressure right where they said, I set accelerator pump with .015" feeler gauge as instructed. I don't know what to do? Getting a carb to run shouldn't be this complicated. I ran an Edelbrock 1406 for years and it ran well out of the box. I have always heard Holley is a great carb, but hard to tune. I didn't think it was THIS true. I'm not sure what my next step should be. I'm just frustrated and want my truck to work again.

  2. #2


    I decided to try and address my fuel problems from all angles, instead of just blaming the carb. I put in new needle & seat and changed the fuel filter. I'm in the process of insulating the fuel lines to make sure it's not a heat issue. The line was hot. I don't think it was hot enough to cause issues, but it was too hot to keep holding. So it won't hurt either way.

  3. #3
    Join Date
    Nov 2014
    Ont. Canada


    One easy way to tell if you're cooking the fuel in the lines, is to cover the vent tubes with your fingers. If it's boiling fuel in the lines, it will pump the vapors past the needle & seat a lot easier than it will pump fuel past the needle & seat. Once the vent tubes are covered it will build pressure and push the fuel out the air bleeds & boosters.

  4. #4


    I'll try that, thanks.

  5. #5


    I bought the carb second hand and it looks like the previous owner did everything possible incorrectly. Probably why he sold a brand new carb. He thought it was crap because he can't read or follow directions. I'm on the last few adjustments now and have the truck running well. I just needs rear jets now that I have the primary jets sized correctly.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
About us
Holley has been the undisputed leader in fuel systems for over 100 years. Holley carburetors have powered every NASCAR® Sprint® Cup team and nearly every NHRA® Pro–Stock champion for four decades. Now, Holley EFI is dominating the performance world as well as our products for GM's LS engine. Holley's products also include performance fuel pumps, intake manifolds & engine dress–up products for street performance, race and marine applications. As a single solution, or partnered with products from other Holley companies - Hooker Headers, Flowtech Headers, NOS Nitrous, Weiand, Earl's Performance Plumbing, or Diablosport - Holley products can give you the edge you need over the competition.
Join us