Drill Carburetor Plugs, Don't Drill Carburetor Plugs ???

[leo]

In this case I'm talking about an Allstate 2405 carburetor (Marvel). I've read and heard about the need to drill out the carburetor plugs to be able to properly clean the blind passage ways in the casting and I've also read and heard "don't drill anything". Opinions from those who have been there would be most helpful.

[AL in NY]

Always drill out the plugs, but start with a drill bit about half the diameter of the plug. Keep enlarging the hole in the plug with increasingly larger drill bits. One of the larger drill bits will probably catch the plug and spin it loose. Never select a drill bit the same size as the plug.

[Carb Guy]

I rebuild only original Zenith carbs. I have several units out in the shop that have been ruined bacause they have been drilled out. It is almost totaly unnessary to drill out the plugs, in all the years I have been rebuilding Zenith carbs I have only had to drill out maybe 3 or 4 times and then only one passage on the bottom half, never on the top half which is the one that always ends up junk when drilled.

[redmodelt]

One of the suggestions coming from the Model T world. If you drill out the plugs, tap them for the small Allen head plugs and seal with Permatex thread sealer.

[Purdy Swoft]

I agree with Carb Guy in post #3 There is just too much risk of ruining the housing or breaking off a drill bit. Once a drill bit hangs and breaks off in the carb, you can throw it in the trash or keep it for a decorator . I have always had good results with 1/16 welding rods and torch tip cleaners for probing passages. I also use carburetor cleaner and compressed air. If this approach doesn't work it goes in the junk , good for parts only bucket.

[Patrick L.]

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I try not to have to drill these plugs and I don't think I can the last time I've had to drill any plugs.
You can usually fish around with a tag wire, soak them and then use a lot of air to blow them clean. Today with the sprays that they have now, like Deep-creep, they can be cleaned pretty easily.

[Fred]

I glass bead with a fine grit & small gun & watch the crud & rust blow away..Rinse well with brake clean & high pressure air and have never had a problem..

[Growley bear]

I use a small diameter drill in Tillotson plugs just to the bottom of the plug. If you don't feel comfortable using a drill motor, a pin vise will work very well. Just drill to the bottom of the plug. Then I insert a small sheet metal screw to use as an extractor. Insert the screw to about the bottom of the plug and grip with pliers and almost like pulling teeth, the plug is out and no drill damage to delicate carburetor housings.

Chet

[jmeckel]

Originally Posted by Carb Guy

I rebuild only original Zenith carbs. I have several units out in the shop that have been ruined bacause they have been drilled out. It is almost totaly unnessary to drill out the plugs, in all the years I have been rebuilding Zenith carbs I have only had to drill out maybe 3 or 4 times and then only one passage on the bottom half, never on the top half which is the one that always ends up junk when drilled.

I agree, I also rebuild zenith carbs and only have ever had to remove 1 plug.
Glass bead blast, proper hand cleaning of all passage ways, and commercial carb chemical boiling cleans them every time like new.