Got my '79 running again the other day. Had a bad starter, remand, was put together wrong. New starter and the grinding went away.

other than that, I think it was just out of gas. SMH.

Anyway, it smells like it's running rich, as was the case when I drove it home. After starting it and running it a few times, it back fired at startup through the tail pipe.

I have no idea the history of this thing. It's running, dare I mess with it? Should I rebuild the carb and put new floats on it?





Previous thread, relating to carb.

https://www.ford-trucks.com/forums/1490221-no-vac-lines-attached-to-carb.html

 

I would attempt to check ignition timing, might need an adjustment. My dentside also had a 460 swapped into it with a ton of vacuum ports. The PO said he could never quite getting running right. Hard to start and was backfiring through the carb. Exact opposite to your problem. Found out the ignition timing was waaayyyyyy advanced.
So maybe yours could be retarded? The late spark would caused unburnt fuel to exit through the exhaust or if it was still burning during exit it would backfire?

Just guesses on my part. But I think it is worth looking in to.

But definitely cap all those lines till you figure out what they're for. I only have 4 vacuum lines now; transmission, brakes, ignition advance, crankcase vent, and other than an exhaust leak it runs smoothly.

 

"Got it running again the other day".

Well that implies it's been sitting a while. A "carburetor rebuild" sounds daunting but it really ain't. The problem is today's gasoline is very hard on rubber parts in fuel pumps, accelerator pumps, check valves, needle and seat, power valves, etc. The residue plugs up the tiny passages and air bleeds and orificeseses. Download the carb manuals - they are all over the web and super useful for setting a carb up right. If it smells that rich it will foul plugs and can wash out rings, dilute engine oil and wastes gas bigtime.

 

From your other thread, if it fires right up, I would guess that the float is fine.

Rebuilding your carb is a great idea. I will bet your power valve is blown, causing your gas smell.

When rebuiling, take lots of pictures of all sides, top bottom, everything. It is very easy to forget. There are 3 screws on the choke that separate it from the carb. Don't completely separate every part in the choke assembly, it is a turd to figure out the first time. Just clean it up really well with a toothbrush. Don't remove the throttle plates or shaft. Check for play, there will be a little bit but too much is not good.

There is no mystery or "dialing in" or "calibrations" or all of the stuff you might think when rebuilding your carb. It really is only cleaning the outside, inside, and merely replacing the wear items. The power valve, accellerator pump, needle and seat, a check ball, and gaskets are all that is in the kit.

One thing that you can invest in is a spacer plate to match your application that deletes the egr all together. It will look nicer than a egr delete plate, and will eliminate a place for carbon to build up. Carbon building up in an egr plate can burn a hole through it, or burn a hole in your gasket and causing a massive vacuum leak.

 

I just can't keep my mouth shut but this is worth mentioning (to me anyways)...

There is no practical reason to overhaul a carb without ascertaining all adjustments are to correct calibration. The kit (quality kit) will come with detailed instructions.

 

The practical reason to rebuild a carb is to clean out passages and orfices of gunk and varnish. When I say that there is no mystery or calibration, I mean that during the tear down or cleaning or assembly. Of course there is idle adjustments, choke adjustments, float height, but that is after assembling.

Most people are willing to learn to adjust the float, adjust the mixture screws, adjust the choke, but shy away from taking a carb apart. I am merely saying that it is not the oo-la-la that someone that has never done it thinks it is.

Adjusting a dirty carb is not practical

 

^^^^ Eggzackly!

Take the time too first to really get the ignition up to spec - good ground and start cables and charging system, hot battery, fresh cap, rotor, plugs, wires, coil. Good fat hot spark.

Then get it timed right, make sure distributor isn't clapped out and sticking and is advancing all the way up (and down) the RPM band smoothly, vacuum advance diaphragm is good etc.

The common error is trying to tune a carburetor when the engine isn't setup right, carb is dirty, it'll drive ya nuts because it will never "hold". The whole thing is based on vacuum signal, carb venturi size, intake plenum etc all working together giving a certain "signal" through the carb.

Just a few degrees off on the timing advance for example, and the manifold vacuum drops off a cliff. The power valve will be stuck open. A 1/16" difference in fuel height in the carburetor bowl is a full point in the AFR. A mechanic's vacuum gauge is your friend here, don't know how anyone really tunes an engine without one. They never lie, if the engine is tuned right it will show it.

 

Agree get the electrical side of the tune-up dialed in first. Cap, rotor, plugs, wires as needed. i have found that wires deteriorate with time... not just miles.

As far as the carb goes - they are easy to rebuild if you know how and practice. That said, there are quite a few things to check and some tricks.

I do not do it often enough to be good at it and buy reman or new.

 

Everyone has very good advice. I prefer a motorcraft kit from the Ford dealer. It will not have a float in it but they have been the kit that I have used and feel that it's the most specific.

 

All good stuff. A lot to read and re read.

Interesting enough, the 6" rubber fuel line from the front tank sending unit to the frame had a slit in it. After running, a vacuum must have been created and was completely draining the fuel tank.

Starter was bad, but no run issue was due to the tank being empty when I thought it was full.

I'll do the normal tune up stuff, buy a timing light and find out how it's timed. Then mess with the carb.