I am having a dickens of a problem with the stupid 1bbl on my six. {Also running a MSD-6 box w/a mallory dist.} I am ***/u/me-ing that the problem is fuel boil {I know, a lot of younger's have no clue what that is} as I have gotten it to behave a bit better by rerouting the fuel line to the firewall, with foam pipe insulation on it, over the passenger fender well to the carb. I also put a small after market air cleaner, the type on the old tri's. She will run without a hiccup all day on the highway, and on cold days. I can do a {very} small amount of stop and go, then she refuses to idle, or idles like there is a massive vacum leak. I'm getting a peice of 22 guage sheet metal to make a "heat barrier" for the carb, but am not totally sure if this will work.

 

sounds like a vacuum leak
this is very possible due to differant expansion rates of the metal
when you can take the time getit hot and do a thorough check
of all hoses and connections
use a carb spray around gaskets and listen for idle changes

 

I'm in South Texas, I know hot, have owned my 83 for 21 years.....NEVER had a vapor lock problem.

 

Ehhhh... Is the heat riser "flapper" stuck open? You can route the fuel lines all you want, but if the base of the carb is being roasted, you may have problems.

Might want to consider an EFI exhaust mainifold conversion if you are in a warmer climate.

 

Dunno...I never really have had that problem on mine. Get one of the "phenolic" spacer gaskets, if you can find one. But actually, it almost sounds like your idle jet is getting clogged, or your float is sticking from the sound of it...Not as uncommon as you would think on the YF carbs..Are you using good filters? Got any rust in the tank?
Also, as one mentioned, make sure the heat riser is working...A clogged idle jet will cause exactly what you describe. Will idle terrible, but run half decent at speed, once you open the main jets up. The only hang...Usually a clogged idle jet will stay that way until you clean it out, or the dirts free's itself up , and it blows through. A stuck float /needle seat from a spec of dirt will do the same thing, except usually you will see gas run from the base, or smell a strong gas smell. MK

 

An ignition box that is dying from heat stroke can cause the same symptoms.

 

Is that the stupid flapper thing down at the base of the exhaust pipe connection?
I also am going to change the gasket between the "emmisions garbage plate" and see if that works. Will a aftermarket intake {OFFY} work with the EFI stock exhaust manifolds??

 

Yes, the offy will work with EFI exhaust manifolds. I think I remember hearing that one bolt flange needs a little grinding, but that may be a universal problem when going with EFI exhaust on a non EFI head.

If in a cold climate, consider getting a carb plate that is warmed (water). Or block off the bottom of the offy (it is made to bolt up to stock exhaust, and thus has a space inside that one could use as a water chamber. But requires some basic metal working skills and tools.

Yes, flapper is at the bottom of the stock exhaust manifold. Grab hold of the weight on the rear (towards rear of vehicle) and see if it moves. I cannot recall which way is "open" and which is closed. But the usual problem is that they are stuck "open", as in opening the heat riser passage to hot exhaust. If its stuck, you can further research by taking the exhaust pipe off and looking up in the manifold. But if the exhaust pipe is rusted and older, that may be a rather destructive method.

You will of course need a new exhaust if you go EFI headers. I seem to read that the ultimate is dual 2 1/2 pipes all the way back, but with a "X" crossover somewhere close to front. This all being what I have read, as I have kept stock for now (though I have my cast EFI headers on a shelf, waiting for a moment of insanity on my part).

 

>>Is that the stupid flapper thing down at the base of the exhaust pipe connection?

Yes. It shouldn't be froze up so it can't move. If it is, spray it with some real good rust buster, and let it sit. Then try to break it loose. Don't overly force so you might break something though. If it won't come loose, keep spraying it and try again later. Just give it light taps with a small wrench or hammer...Eventually it should come free. Mine was totally froze up, but it came loose eventually. I have to spray it every once in a while or it gets "sticky". A test to see if it's working right, is to look at it with the engine cold. It should be in the closed position. Then start the truck, and rev the engine a little bit. You should see the valve open some from the throttle increase, but drop back to closed at idle. Once the truck is warmed up, it should be in the open position. MK

 

That May very, very soon for me, "I feel the need for speed!" I "cured" 90+% of the idle problems by changing a $2 gasket. Boy, do I feel stupid! After the message from mhg about metal expansion , I checked the "Spacer to manifold Gasket", and the dang thing is about shot. All these years, and I still get amazed by how the simple problems always get complex with our intervention.