If i put 20 bucks in the tank, i'll be almost on empty by the time i get home from work. its only 7 miles to work and 7 back. I have to ride on the clutch just to get it to go in first gear if i'm at a slight incline. Theres no way in hell i can go up an actual hill from a dead stop. it takes about a minute and a half to get to 60mph, and thats if theres no slight inclines. I can go up a slight highway incline in 3rd gear decently. the rpms sound good in 3rd, but 4th gear seems to perform and sound terrible, even on flat ground. i can only accelerate in 4th going downhill. 5th gear is a pipe dream i hope to see one day.

when i first bought this truck a year ago, it ran decent but backfired like crazy, and dieseled when i shut it off. i put in a weber clone carb, and it still backfired. i replaced the spark plugs, wires, rotor, cap, and even the ignition module and coil. i played with the timing and added a fuel regulator, until a buddy told me that the regulator was likely unnecessary. doing an egr delete and removing all vacuum lines got rid of the backfiring and dieseling so far. however, for some weird reason if i turn the mixture screw down all the way on my carb, the truck still idles fine. I haven't tried to drive it like this, but it scares me that closing that screw seems to do nothing. its set at 1 1/2 turns at the moment.

I'm not experienced, but the issues I'm having seem to match a few different potential issues: either timing chain, aap problem, or carb. I was hoping someone here could list more in depth symptoms of those issues to see if anything matches my problem. knowing my luck, I'm getting hit from all three, or more.

 

If the fuel is leaking out onto the truck, ANYwhere, or the ground, you absolutely NEED to find it and stop it. That is a fire hazard that is scary dangerous! The fuel filter is located on a frame rail, passenger side, just forward of the rear wheel. Check around it. If one of the hoses has a crack, or hole, or is loose, the fuel can really come pouring out. Deadly dangerous! No matter what, find out WHERE that fuel is going an stop it. ASAP!
If it's going down the carb throat, sounds like that Weber clone is bad, and needs to rebuilt and/or replaced.
Same with the mixture screw. You absolutely need to find out just why it's having no effect. It should. If the fuel is going down the carb throat, that may be why right there.
Is the choke plate opening completely? Or even at all? If not, that is another possible reason for the fuel loss, and the lack of mixture screw effect. The choke system has an external thermostat, mounted on the air cleaner bottom half. Make sure it's functioning correctly.

Set the timing to factory specs. It's what the engine is designed to run on. Verify that the spark advance modules on the distributor are functioning correctly. Make sure the distributor spark advance functions correctly. The plate in it that the external modules move to alter the spark advance. If it's sticking, or not moving, it may be the distributor is stuck at a specific advance, not backing off or advancing.

The factory carb has an "anti-dieseling" valve that's supposed to shut the fuel off completely when the key is turned off. Sounds like it wasn't working. They're very easy to replace, and cheap.

The timing chain is pretty easy to check. Just pull the valve cover, and you can reach down along the chain with a screwdriver, or something similar, to see if the tension is correct. You can also visually verify that the chain tensioner and the chain guide opposite it, are both still in good shape. Or even there. The guide has been known to come apart and drop into the oil pan. You may need an extendable inspection mirror to get a real good look. That, and a decent flashlight

I don't know what, if anything, is going to be any help, but I hope something does! I was just throwing out ideas. The only thing I will stick to like mad is find out where the fuel is going Otherwise, you might come out of a store to a nice bonfire. NOT good!

Good luck to you!
Pat☺

 

Much appreciated. I'll get to going down that checklist soon. unfortunately i had one step forward and two steps back today. First, there was no visible fuel on the ground, so i'm assuming its in the carb. i blocked off the aap port and the vacuum advance hose, and advanced the timing slightly. the gentleman who worked on my truck had the timing completely retarded. retarded as in no advance at all, not in a derogatory way. which is still kinda retarded though. doing this helped the truck run and shift better, but i had two extremely bad backfires in the exhaust that cracked the muffler, and a final third backfire that completely split the muffler open. i can fit my fist in the hole. so i'm gonna go ahead and assume the raw fuel was just pouring down towards the exhaust, which is still weird as it wasnt dripping from the exhaust beforehand. i just welded that brand new exhaust about a month ago, since the stock exhaust blew up on me in the same way. i erased the catalytic converter assuming that it was plugged and causing the explosion. this all had happened before installing the weber clone, hopefully meaning that the carb isnt the main issue, just a contributing factor.

again, i appreciate the point in the right direction. i'll start marking off that checklist.

 

Does your 32/36 clone have an electric choke? If so, check that the choke is opened properly when the engine is at operating temperature. I had problems with choking issues on my 32/36 clone and ended up just buying a manual choke conversion kit. Good luck with troubleshooting.

 

From what I read in the FSM, with the vacuum lines pulled off the two spark advance modules, and blocked off (a small screw of some sort works great!), the timing should be set to 0°, at idle RPM. 850 RPM is "nominal". Once the timing is set, re-attach the vacuum lines. The timing should go to 10-14°. Depending on your altitude. It goes a little further where I live, at 4300' MSL. If not, check the spark advance modules. Their diaphragms are known to tear loose. That will stop them from working completely. BAM! Backfires, etc.
Make sure the air gap of the pickup coil in the distributor is set correctly. It should be 0.008-0.016 inches (0.2-0.4MM). That's important. Also, measure the resistance of the pickup coil. It should be 140-180 ohms.
As I mentioned, make sure the spark advance works. The plate in the distributor should rotate fairly easily. Not totally freely, but with just a slight amount of resistance from it's springs. Make sure the throw-out weights are free to move.

Of course, if the choke plates aren't opening completely when the engine is warmed up, and dumping raw fuel down the throat in gallons, all the above is moot. Fix that first, obviously

Good luck. Let us know how things go for you. Your experiences may help the next guy
Pat☺

 

you guys both mentioned the electric choke, and thats the funny thing too.

so when i first installed the weber clone, i wired in my old electronic choke to it. there was a video online that showed me what hole to put my wire into on that plastic piece, and it worked.
that being said, i recently had issues starting the truck because the choke wouldnt open at all. this didnt happen until after i let my mechanic friend play around with it. I adjusted the choke by fiddling with that round piece on the carb thats held on by 3 screws and attached to the electronic choke. To be honest, i dont know what that round piece is called. is that the aap? either way, i adjusted it until the choke plates just barely started to close while the engine was warm.

i havent checked my timing again yet, as the truck is running like garbage since the muffler exploded. but i completely removed the vacuum hoses to the spark advance. i was told to try this to see if it would fix my fuel dumping issue. i removed that hose and plugged the port from the carb. it did seem to help my rpm/ throttling issue, as i was able to go uphill in fourth gear at a constant 55mph, though it was kind of slow. but then the muffler exploded. im not sure if the fuel issue was fixed, as i havent drove it again since the muffler incident.

 

Sounds like the muffler had a build up of fuel vapors in it that finally reached ignition. The truck IS going to run like crap with bad muffler. Definitely get a new one in there.

The FSM specifies the idle mixture screw should be 3 1/2 turns from bottom as a starting point. Just thought you might like to know...

Can you maybe post a picture of the "circular thing" you adjusted? That isn't what you adjust to adjust the choke opening, whatever it might be. That's all done with the little bars on the outside. You bend them slightly to make them "longer" or "Shorter". If you want, I can put up a pdf with the adjustment procedures in it.

Personally, I would check to see that the vacuum advance modules on the distributor function correctly, and hold vacuum properly. A vacuum pump with a meter on it is a cheap, but essential item of test equipment for this, although, as a quickie check, you can apply vacuum with your mouth, and hold the vacuum hose closed with a lip, or tongue. You won't have a meter to verify the amount of vacuum applied, so go very, very, gently. You can visually determine if the modules advance the distributor properly, and whether or not, if they DO advance the distributor, they hold vacuum correctly. Again, go VERY gently, or you can rupture the diaphragm with too much vacuum.

You can also check via the timing. With the vacuum lines disconnected, and plugged off, it should be 0°, and when you plug the vacuum lines back on, it should go to 10-12°. That won't tell you if the modules HOLD vacuum as they should, but at least it will tell you if they're at all functional. If you advance the throttle a little, with the vacuum lines off, and the timing changes, that tells you the throw-out weights are functioning correctly. Again, be VERY gentle with the throttle.

Good luck, and keep us up to date on how it goes
Pat☺