[redfishtony]

I am rebuilding a 69 U152, 302, 3 speed. Truck is all stock and I hope to keep it that way. I recently rebuilt the carb (autolite 2100) and the truck will run fine one minute and rough the next. I have tried to adjust the carb and the timing and just when I get it set where I think it is correct it will start to run rough as soon as I rev it up. If I punch the gas several times it will sometimes smooth out but most of the time it wants to stall. Any suggestions? Also is there an easy way to adjust this carb. Someone told me the power valve in the rebuild kit was probably defective and the carb was sucking air through the valve making the truck act this way. Thanks for any advice. TW, Thomasville, GA.

[Bronc76]

sounds like you have an idle mixture problem, have you replaced vacuum lines, (might be a leak). when was the last time it was tuned up?

[Bully Bob]

Hay Tony.,
Those carbs are pretty simple.., you can't hurt it by starting over & inspecting it.
1st., take the airhorn off while carb is still attached...(run the eng. a short time first) & visually check the fuel level in the float bowl.
If you remove the carb.;
I would closely insp. the idle circut.., and the fuel inlet needle valve. The slightest debris in either can cause problems.
Of course, the float level adj. is pretty important as well.

Having said that., & prior to the above.,
What was it doing B/4 the carb rebuild.?
Dirty gas tank., obstructed fuel lines., blocked switch-over valve., plugged filter., & a weak, or leaking fuel pump.
---- Other items of interest.... base gaskets & vacuum leaks at the PB booster (internal)
Any or all of these can cause headaches..!!!
I doubt it's the power valve.

As far as ignition., start at about 6-7 deg. & with the timing light operating.... the mark should stay steady as the light flashes. If it jumps around....there could be a timing chain issue., in addition to the above.

HTH

B

This post has been edited by Bully Bob: 19 May 2009 - 11:06 AM

[redfishtony]

Thanks so much for the information. Looks like I (we) have more work to do..... As for before the rebuild, the truck had sat for almost 8 years. It was stored in a neighbors barn and had not been cracked in 8 years. When we got it to my shop we had to pull the fuel tank and replace it. I tried to have it cleaned but found several small holes that were not fixable. While waiting on a new tank we did get it to crank off of a temp tank. At that time, believe it or not it seemed to run fine. We were all very suprised. It was at that time I decided to go ahead and rebuild the carb. As for the tune up, I have new plugs and wires but have not installed yet. I am planning to do so before I do anything else. The truck has a distributor and it is powered by what I am asuming is a electronic ignition box. I'm not sure if this was stock on the 69 but it looks original. For the time being, me and my 2 sons are just having fun trying to learn all we can as we go. They are 15 and 10 so this is an exciting project for them. (only problem being, they want big tires and MUD) Anyway, thanks for the support and the great source of information. Sincerly, TW

[Bully Bob]

Ahhhh..,
All the rigs I got., aft. sitting only two+ yrs., ....one of the first things I do is clean the fuel system. i.e. disconnect all fuel lines & blow carb cleaner thru with an air hose., (you wouldn't believe what came out of some of those lines.) Insp. that valve & tank flushed if necess.
Then new filters.
Sitting that long..the fuel pump bladder may have issues. Particles fr. it may have traveled to the carb.

"The truck has a distributor and it is powered by what I am asuming is a electronic ignition box. I'm not sure if this was stock on the 69 but it looks original."
NO.... it's not.., but it's probably OK.

Tires/big wheels that's a whole 'nether science..!! Do your homework B/4 you get into that....wheels., backspacing., gearing., steering., etc.

Have fun..!

B