WARNING!! Holley Carburetor Defect!

[MWCC]

I wanted to let everyone know that I came across an issue with a Holley carburetor that I installed on a customers car back in 2007. The car has been back at my shop getting some minor changes and it developed a drivability issue. As time went on, the idle became irratic and it developed a stumble at initial throttle. I suspected the carb was dirty but boy was I wrong. Dirty was an understatement. Last Thursday the car would barely idle so I finally pulled the carb to inspect and what you see in the pics is what I found.

I have been repairing and restoring cars for close to 25 years now and have never seen this. I can't even count how many carbs I've rebuilt. I even had a local customer in the shop who is also a racer and huge Holley fan and even he was shocked. The corrosion and expansion of the material was incredible. I went to Holley's website and found a press release pertaining to a recall issued by Volvo Penta and the US Coast Guard relating to what they called "accelerated corrosion" issues with the metering blocks and fuel bowls on the marine carburetors. Holley actually called it a performance issue (made me laugh). At the bottom of the release they also stated that some non-marine carbs could also have the same issue. These carbs were manufactured in 2005 and 2006.

Guys, if anyone who reads this has one of their units manufactured during '05 and '06, pull it off and open it up!!! Some pieces are small enough to make it through and into the motor. You can tell what year your carb was made by the casting clock located on the unit. It will have a 05 or 06 surrounded by two circles and 12 small boxes between the 2 circles designating the month. A dot in the boxes will give you the month. The other way to tell is by the stamping directly below the part# stamp on the air horn.

I called Holley and they are sending me a new unit. They were very courteous and professional and will replace the bad units for free. If you have one of the bad units, you need to call their Tech line at 1-866-GO-Holley and they will send you a replacement.

[MaxHarvard]

Holy crap! Thanks for the heads up!

[wedged]

I bet the defect is caused by the fuel. It seems not too many considered the consequences of adding alcohol to gasoline.

[MWCC]

Originally Posted by wedged

I bet the defect is caused by the fuel. It seems not too many considered the consequences of adding alcohol to gasoline.

Actually it is a casting defect. I spoke with them and they told me the issue has not been found to be related to fuel but in their exact words a " casting problem". I have a lot of experience with casting materials since I was a Toolmaker for almost 20 years and worked in a casting facility for a number of years. They probably made a change in the casting material or the process to cut costs and it bit them in the A$$. I have had Holley carbs forever and have never seen this. I have a 650 DP on my shelf that I have been using for 20 years and it looks as good as the day it came out of the box. These new carbs are getting different coatings and there also could have been an issue with the coating process having an incompatability with either the casting material or the fuel. Once the electrolysis starts on parts like this, its impossible to stop it.

[GregWeld]

Originally Posted by wedged

I bet the defect is caused by the fuel. It seems not too many considered the consequences of adding alcohol to gasoline.

Wedged --

You know it's NOT THE FUEL - because it's a specified date of manufacturing. If it was the fuel - it would be every Holley ever made.

[MWCC]

Originally Posted by GregWeld

Wedged --

You know it's NOT THE FUEL - because it's a specified date of manufacturing. If it was the fuel - it would be every Holley ever made.

Your absolutely correct. The fuel bowl from this carb should have looked at least as bad as this metering block does. It was spotless!!! Not a sign of corrosion anywhere. The rest of the carb including the secondary bowl were spotless as well. This is definetely a manufacturing defect.

[Vegas69]

Thanks for the heads up....I'll have to check mine out next time I pop the hood.

[Iamtheonlyreal1]

I have one giving me fits at this time.. It was new last year and ran great, but when I started working on the car again, it runs like total crap... I guess I will open it up..

[wedged]

Originally Posted by GregWeld

Wedged --

You know it's NOT THE FUEL - because it's a specified date of manufacturing. If it was the fuel - it would be every Holley ever made.

It's entirely possible that the specific metal they used for the metering block won't tolerate some additive in the fuel and the rest of the carb is made of a different material. I'm not saying I'm right, just that it is possible.

[Spiffav8]

Holy Cow! Thanks for posting the information and the pictures! Good chance you saved a few guys from a lot of headaches.