carberator rebuild questions



hey there. i just re-built my engine(66' 200 mustang 3spd) and now im ready to take on the carb re-build. im working with a holly 1940 and i am re-building it because i dont beleive the accellerator pump is working right and the choke doesnt work plus it is dirty and it needs it. is there any advice you guys can give me on re-building them?? i know you guys have done them lots before??

do you think it is the accellerator pump when... i cant punch it! and when im in third i can barly put my foot on the pedal.??

p.s. i just put in a msd blaster 2 coil and man did that make a difference!! i didnt expect to have it be that different but the throttle responce was way better and starting it is like a touch of a button now!!
so exciting!

First On Race Day
If the 1940 is similar enough to the 1946, on which I have LOTS of experience....

The top plate of theses Holleys tend to warp. When it does, the power valve will barely close or won't close at all, dropping open whenever the throttle is moved off of idle. Eventually, it even leaks at idle.

When yours is apart, check for flatness on the top plate. It may be millable if warped - see a carb shop. It costs about $20 to get it done.

Don't use any gasket cement anywhere as the gasoline will wash it all off. Sometimes the cement can end up in the smaller passages then and become a headache.

Finally, get a set of 12-24 size helicoil inserts. Chances are, when you reassemble it, one or more holes will strip. If you can, start out with new screws (Ace hardware carries the right sizes) and plan to helicoil anyway. Again, carb shops will charge about $25 to do the helicoils if you bring it in disassembled already. It really helps keep the leaks down later.

After you've driven the new carb about 500 miles, take it off and tighten up the lower mounting screws. They will be 1/4 turn loose, no matter what you do. Same story on the upper ones. Even if you buy a brand new one, like I did after my 12th rebuild, this loose screw business still applied.

Good luck!