Dead spot in Carburator

[Tison78_CJ5]

'78 CJ5 with 304, everything manual.
I have a dead spot in my Holly carb, (2 barrel) that seems to be getting worse.
The last owner said he rebuilt the carb. because of the same problem.
I have tried adjusting the choke, which I think helped a little.
I checked the distributer, pulled off the vacuum advance, made sure it was working good.
Advanced the timing some, but still dies.
It is annoying because every time I change gears it jumps and burns rubber.
I wouldn't mind it I meant too.
Does this sound like I need to tear into the carburetor again. It did sit for about two years in the weather before I got it?
I was hoping to nurse it along, till my other engine is finished. I am putting a 4 barrel Holly on it.
But this is starting to be an issue, I think I need to fix before it causes a problem in traffic.
Thanks, for any suggestions/thoughts....

 

[PoliceMonkey161]

When you say dead spot, is it bogging down / cutting out at certain throttle positions? Then does it seem to "catch up" all the sudden?

 

[Tison78_CJ5]

It acts like I have switched the key off. It is probably around 2000 rpm. During acceleration. If I let off, or push harder it takes off, throwing you back in the seat.
It is one small spot in the throttle that this happens.

 

[Tison78_CJ5]

It acts like I have switched the key off. It is probably around 2000 rpm. During acceleration. If I let off, or push harder it takes off, throwing you back in the seat.
It is one small spot in the throttle that this happens.

 

[PoliceMonkey161]

If we where talking about a Weber downdraft carb (32/36, 38/38 etc) this would be an easier troubleshoot for me to help with, but the principles are similiar. From the sounds of it, you have something delaying the start of the secondary (or primary, not sure how Holley breaks that out?) circuit. Something is causing a delay in tripping the the next fuel circuit in the seqenence. It can be the float level, a clogged jet or in an exterme case, a defective accelarator pump/piston. Good news is if I remember correctly, all of these can be checked on the Holley w/o a major tear down. I will need to breakout the Holley manual and fresh'in up a bit. Maybe one of the other guys who is more familiar with Holley's can chime in?

 

[Tison78_CJ5]

Thanks, I believe I have eliminated every thing else. I just hate to get a rebuild kit, and do a rebuild on it.
But, I don't want to drive like this, till my new engine is completed in a few months.
It did sit for a long time before I bought it, so the carb is probably full of varnish/crud.
I think I'll run to the local parts house and get a rebuild kit ordered.
That bumbs me out, I know when I pull that engine, and put it in mothballs, it will probably need to be rebuilt again.

 

[superj]

So it does it at 2k rpms? That's to high to be caused by the enrichment circuit not keeping up with the lean spot caused by off idle acceleration. 2k is totally the jets.

Are you running out of fuel? Or is it not accelerating and then you rev it and around 2k it starts working right?

 

[69jeepcj]

check float level by removing the sight plug on the side of the float bowl, the level should be right at the bottom of the sight plug hole, to where if you rock the vehicle fuel should spill out the hole (holleys are very sensitive to float levels). That would be where I started, if it still does it I would try blowing out every passage I could. If its not the float I would think clogged jets as mentioned.

 

[Tison78_CJ5]

Thanks for all the suggestions on my carburetor.
I pulled it off this morning. It was full of trash and, screws loose.
I used two cans of cleaner, and dawn dishwashing detergent with a tooth brush.
It is perfect. By the way, it turned out it is a Motor craft not a Holly. I can't read well.
Anyway I am tickled pink.
Thanks.

 

[69jeepcj]

Glad you got it worked out.