Ok, first time rebuilding a carb here, so bear with me. I have (according to Napa) a motorcraft 2100 carb I've pretty much rebuilt. I'm just stuck on how to adjust the float. Where do I measure, what do I measure and how do I measure it?? I've been through the rebuild instructions, a haynes manual and another book on card rebuilding, and I have no clear idea how to go about it. All the measurements are either WAY off or I'm measuring the wrong part of the float, or measuring off the wrong part of the carb. HELP!

Oh, the tag on the carb says Motorcraft D4TE HA B 3K 2. According to Haynes, the dry measurement for a 79 351M is 31/64, and the wet is .875. What I don't know.

Thanks all.

 

After you have the brass seat properly installed in the fuel bowl, set the float in the bowl as it would sit once finished. Take your finger and gently push on the float tang so that the needle seats. The other end of the float will raise up. You want to take the measurement while keeping it pushed like that. The distance to measure is from the raised end of the float (the point right before it curves down to form the side), and the top machined surface of the bowl, where the air horn gasket rests (the measurement is vertical). Use the little cardboard ruler that comes with the kit.

To dial in the height, bend the float tang appropriately until you've got it nailed. Don't be alarmed if you have to adjust it some, since the rebuild kit could have a taller\shorter seat than the original did. Also, don't forget to snap the float retainer back in place when you're done.

 

So is that the wet or dry measurement? And if its wet, then is it supposed to be .875 inches?

 

That was for the dry measurement. Wet measurement is a different procedure. You take the dry measurement when you are rebuilding the carb, and hopefully that is all you will need to do. You would do a wet measurement if the carb is on the engine and you are having problems, and need to check the height when there is fuel in the bowl (hence the term "wet").

For what it's worth, a wet measurement is done by idling the engine, and removing the air horn from the top of the carb with the engine still running. You measure vertically from the surface of the fuel level to the top machined surface of the fuel bowl. If the height is off, then you have to shut it off, take the float out, bend the tang, re-install it, and do it all over again. You have to be really careful when doing a wet check because the engine is running, and you also have an open fuel source. Plus, if you bump the float with a pressurized fuel line, the needle will open and gas will shoot out of the seat. This will also happen if you have to take the float out to re-adjust it. It's really a pain. But if you do the dry check right, you shouldn't have to worry about this.

Anyway, when you're just putting the carb together, you will want to do the dry measurement, and the procedure in my first post is for a dry measurement.

 

great, trying it now. Thanks. I'll let you know how it turns out.