I'll give a bit more history on my truck now. It's an 80 F-100, with a 79 [not exact, but it's that generation.. ] 3/4ton 400 big block. I was told it has a C6 tranny. It's a 3 spd, and would like to know how to tell what it is though. The truck has sat for quite some time. Never really driven before me with the motor that's in there, and it sat about a total 2yrs. But it always ran for those 2yrs.

Now, here's what I've got. It needed a fuel filter, okay check. Drive 5mi, things clogged, truck runs, but isn't going anywhere. Pull it out, carb clean it good to go. Fuel is dead rust, it spilled on my upper rad hose, and it dried pure rust dust. Okay, i'm off, right? Wrong, another 5mi same story. Obviously I need the tank cleaned. But the truck doesn't mind the gas otherwise. Is there a way I can avoid the tank cleaning by just running the truck and cleaning the filter when it needs it? I haven't access to a siphon pump, nor the cost of gas to flush what I've put in, out [this is a very broke week]. I also don't have a working fuel gauge, so keep in mind that on any tricks you guys have.

Also, my headlights suck. Absolutely crap. I couldn't tell the difference between a car and a kitten 15ft in front of me. The wiring looks a bit trashy, but it all looks like stock unmolested stuff. I know it's possible to hardwire in some better stuff, but is it just the bulbs being incandescent [only 99% sure on that one?]?

One last thing. I don't know a whole lot about carbs.. basics, but there's no experience on my part. The truck seems to run a bit rich, because when the fuel filter clogs up the truck seems to have more bottom end power, and occasionally it'll flood on startup. It's just a stock 2bbl carb, probably off the 79 motor. I would like to know how to tune it. I know it would be best once I get some good gas running through there, but I'm still listening

Oh, oh wait, one one last thing, I promise. There is a bit of oil that comes out of the carb spacer. And it pools on the intake. I can never see it do it, and it's not a lot of oil, maybe 10mL on the intake. But it's definitely oil, and it's definitely coming out the carb.

 

Take the gas tank out. That dirt will aggravate you for years to come, and one little chunk in the carb, and you will have fuel all over the engine. I bet the carb is filthy inside too. While the gas tank is out, you can test the sending unit, which is probably why the fuel guage doesn't work.

With the lights, check the voltage on the battery with the engine running. It should be around 14 volts.

I just read the next question about the carb. Dirt, dirt, dirt. Clean the fuel system. when you get the fuel tank cleaned out, take the top off the carb and clean the bowel out, and take the main jets out and blow them out. You have been really lucky so far that it is still running.

The oil on the intake is probably coming from the PCV valve. Do you have chrome valve covers? If the PCV valve is hooked to a large nipple on the rear of the spacer, then that's were the oil is coming from.

 

Dave is right on the money about the fuel issues. If you don't drop the tank and clean it you'll forever wish you had.

GE makes a high output sealed beam H6054HO that I found work quite well. The low beams are 55w as opposed to the standard 35w. I bought mine at Wal-Mart. A noticable improvement over the Sylvanias.

 

Not news I wanted to hear. Is dropping the tank possible bed on? It's the rear tank, the front one is there, but there is no filler neck for it. The truck doesn't mind the gas, it's just the fuel filter lol.

The PCV valve setup is all messed up. It's hooked up to a vacuum line at the very back of the intake. It's shared with the brake booster and one other PCV valve. The one on the passenger's side works fine, the driver's side is total garbage. I disconnected the passenger's side one, along with the driver's side one [but that one was worthless] so the booster would work. I've only driven it maybe 5mi like that. I know it's not long term, but I'd rather be able to stop. However the oil pooling I noticed before I messed with any vac lines. Still can't see it happen.

The voltage at the battery is 14.3. The voltage at the lights is about 11. So, I found that problem.. but the bulbs really do look original. I need to first get the truck running better, then I'll work on the lights, but now I at least have a part number.

EDIT: I was playing with the fuel switch and the fuel gauge came on for a sec. It read below a 1/4 tank. So I gassed her up, full tank [yet to even fill the truck up, dude I bought it from told me he put in 10ga, and haven't been driving it that much]. The fuel gauge work twice, reading a full tank, then it crapped out again... maybe it'll make another appearance in the future. Guess I'm countin' miles .

 

You certainly can drop the tank with the bed on. A lot of people on here recommend taking the bed off, but that leads to a whole other can of worms that I would not want to get into myself. Just be careful if you drop the tank and it has a lot of fuel in it. Get a floor jack and put under it. That fuel is heavy.

 

for your head lights check your ground conections. being at the front of the truck,they get moisture and corode.i have had to do this to many vehicles.once you have everything cleaned paint it or usebattery termanal protector,that should stop the conections from coroding.
on the fuel system clean it with muritac acid or replace the pieces,i had the same problem once and caused me nothing but grief.clean the whole system to

 

Take everyone's advice and drop that tank ! There is no other way but the hard way. I did it the hard way for 2 years, figured I was smarter than everyone else and could avoid the hour or two it ultimately took. Meanwhile I went through 3 carbs, 2 mechanical fuel pumps, filter after filter after filter ad nauseum, countless hours on the side of the road fixing it or pushing it, and looking pretty stupid to friends and family. I could not believe it was as easy to cure the problem as it was, and I should have done it when I first got the vehicle as a matter of course (it had been sitting in a farmer's field for 7 years - in the same spot where the former owner turned it off one day, on its own tires, and never turned over or touched in all those years !). In the end, I replaced 100% of the fuel system, including new 7/16" lines, new electric pump, two inline filters (low pressure one installed between tank & pump, high pressure one with a chrome & glass sight bowl installed between pump and carb), a new Edelbrock #1805 4 barrel on a Performer Intake, an auto wrecker's used tank (finally !), gas cap and all hoses, all-stainless clamps, and new sending unit and custom fuel gauge. It sure is nice to be able to view the condition of my fuel without turning a wrench, getting wet with fuel spillage or smelling gasoline ! That inline filter cost about $20.00 and came with 3 plastic washable/replaceable elements which have lasted 4 years so far. Easy to change, and they wash up well in gas, solvent or diesel. But clean or replace that tank - its the best $100 you'll spend on that truck !

JT

 

I've been thinking, and driving the truck a bit, and I'm going to take everyone's advice and just do it. No point in doing anything else until I get this done. I have the next two days to devote to cleaning everything. I'll need a bit more info on what I need to do to get it out. I haven't even looked at anything real close down there, so I apologize if it's real straightforward. No idea how much gas I've got, driven about 160mi on a full tank. But that's kinda beating on the truck a bit, but also with a clogging fuel filter... so... who knows what I have in there. It's all crap gas in there, so I may as well just dump it and forget about it. The fuel smell, although nice in moderation, is really getting to me every freakin' 10 miles. Just to make sure, there is a drain valve on my rear tank that will get the majority of the gas out?

Also, I would like to, maybe not right now, but shortly possibly fix the rust hole in the front tank. I read that there can be problems with the thing that switches the fuel when it doesn't get used? What kind of work is involved in that? Replacement or just new o-rings?

 

While you have the tank and carb off, disconnect the fuel line from the gas fume filter (a plastic container on the right front inner fender) then blow out the line with some low to moderate compressed air. Loose sediment will come out also.

If that truck has been sittting a while you might replace all the rubber fuel sections on the line as they could be cracked.

 

Well! After 4 years of taking the tank off and cleaning it out 2 times and replacing filters every 100-150 miles after the tank cleaning my Dad took my advice and replaced the tank! It will only rust more and more and clog filters at the worst time! Been there and destroyed the T-shirt changing filters!

My point buy a new tank!

 

Well, I am going to assess the tank once it's out. I am keeping an open mind, because if it's crap, obviously I am not going to waste my time on it. But I'm crossing my fingers that it's not going to be too bad. But the rust colours i'm seeing out that filter are a real deep dark red/brown... an old strong rust. So... we'll see what comes up .

 

Well folks, did the suspense kill ya? I know it sure did me. Tank turned out to be garbage. Not only did I break every bolt pulling it out [trailer hitch bolts, and tank bolts], but that tank is crap inside and out. Upon inspecting some of the rust on the inside I discovered a nice little pinhole waiting for me. I don't think that was there in the beginning, but wrestling the tank out of there probably did it. Rust is one nastly *******. Gave a call to the local yards, none of them have a good 19ga ford tank. Couple of them were saying by the time they end up here their usual problem is the tank. So, a new tank for the tune of $100 is about my only option. The gas that came out of the tank wasn't even clear.. or semi clear... or translucent. It was freakin the nastiest brown gas I have ever seen. There were chunks of rust that were coming out and getting stuck even. I'm not sure which was the outlet line... there was the top PCV-valve-looking thing and the side guy with the connector on it. The side guy was kinda just loosely there... maybe on maybe not... but it still had gas in it, and it was the same nasty crap that came out the tank.

 

Do yourself a BIG favor,and replace the steel fuel lines also.

Leo

 

Should I do it because bad gas went through them or because they are old? They look as though they've been replaced and are in very good shape.

 

I would replace them just to eliminate the possibility of more crud flushing out of them,unless you can thoroghly clean them out.

Leo