Holley 2280 Troubleshooting

Holley 2280 2 barrel carburetor troubleshooting
The power piston is staked at the top so that it doesn’t come out. Use an awl to scratch the staking off, then flick the piston with your finger until it pops out of the hole.

Carburetor flooded. Rebuilt the carburetor and ran fine for 1,000 miles. Started flooding again.

  • Test the float – Nitrophyl is weighed with a gram scale.
  • Brass – heat up a pan of water just prior to boiling. Immerse the float and look for bubbles.

Here is what I suspect. The float is absorbing fuel. When you had it apart, the float dried out. It slowly absorbed fuel again.

The carburetor may also have gotten dirt in the fuel.

When you take the top off, look at the bottom of the bowl for any sign of dirt.

If there is dirt, then make sure the fuel filter is replaced.

The gas tank could also be dirty.

  • For a brass float heat up a pan of water just prior to boiling. Immerse the float and look for bubbles.
  • Test the needle & seat. Blow through the inlet (remember only 4. to 5.5 lbs ) with the float closing the needle, air should not get through.
  • Test the fuel pump for proper pressure. Too much pressure will cause the needle to open too long.

Check Weight

There is a check ball, then check weight that is placed in the main discharge underneath the venturi cluster.

I have a problem adjusting my holley 2280 on my 1987 dodge d150. It has a 318. I bottomed out both mixture screws and its still backfiring and running a little rich. I need help bigtime. Will this hurt my 318? Should i turn them both out 2 turns? I need help… 


This is an indication of a carburetor needing to be rebuilt, or if you just rebuilt it, something was installed, or adjusted incorrectly and it is very hard on the engine. 

  • Blow out any idle passage. They usually travel from the idle mixture how up to the venturi.
  • Check the float level.
  • Test the float. Nitrophyl type is weighed with a gram scale. 14.5 grams
  • Test the brass type by heating up a pan of water just prior to boiling and immerse the float. Look for any bubbles which would indicate a leak.
  • Test the needle & seat for leaks.
Updated on 01/18/2021

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