Greetings all, new guy here.

I've got a 1968 F250 4x4, 240 straight six. It was a Forest Service truck, and has a mechanical winch with a PTO on the Dana 24 case. The ticker's got about 75k miles on it, I have no idea how many times it's rolled over, but I'm sure its a few. It leaks a bit here and there, but on the whole has been pretty reliable, and is a pretty good around town truck here in the Colorado Rockies.

I'm having some carb issues now, and I can't quite figure it out. It's a Ford 1 barrel (which I've seen referred to as an Autolite 1100 as well). I've found that every 6 months or so I need to open it up and clean out the carb, especially the inlet/float needle area, or I start getting fuel starvation issues, no big deal. I stalled out the other day, same as has happened in the past, cleaned it out, drove a few more days and it died again. It wasn't all the way dead this time though, in that I could start it, get a couple hundred yards, and then stall again. I managed to get it home that time, and decided it was time to buy the full carb kit, as I've heard that those vitriol float needle ends can start sticking after a while.

When I pulled the carb, the bowl was dry, as I expected. Much to my dismay, neither of the two float needles in the kit fit my carb. The kit even had a new float needle seat that you can thread in, but the seat in my carb is pressed in, and the new needles are both too wide to fit in the seat. So I very carefully cleaned the vitriol face of the needle with 500 grit sand paper, and put it back in. I put it back together, and it started and ran just fine (yesterday). So today on my way to work, it started losing power like it was starving for fuel. I was in front of a bus stop, and about to enter a construction zone with only one lane open, so I just parked and left it there to deal with tonight, rather than risk being the guy who corks the bottleneck during monday rush-hour. I'm assuming I can make it home from there, but not positive.

So a couple questions:

1) anyone know how to figure out what vehicle my carb came off of so I can find the right kit for it? I didn't see a part number stamped into the carb housing, unless it's on the bottom of the outside of the float bowl. I'd like to avoid buying a whole carburetor if possible.

2) Any ideas what I should be looking at, other than the float needle? The fuel pump is definitely pumping. You could say that it starts cutting out when it reaches operating temps, which would point to the coil, but since the bowl was dry when I went in there, that would mean that the coil coincidentally failed on the same day that I fixed the carburetor issue, and has the same symptoms as the previous problem, which does seem like a long shot.

 

So no comments then, eh?

I did get the truck last night on my way home, and it made it home, although I had to pull over and let people pass a few times, because it would start starving for fuel right about the time I'd start thinking about shifting to fourth each time. When I'd pull off, it wouldn't stall, so I'm assuming that I'm getting enough fuel in there to run at lower RPMs, but in the higher range it's burning fuel faster than the carb is getting it.

When I had the carb apart this last time, I checked the float and adjusted it slightly - the spec calls for a float level of 1 3/16, and it was closer to 1 5/16, so I fixed that, but if anything that would give me more fuel, not less (right? I haven't had any coffee yet today). I didn't adjust the drop, figuring if it ran before and it's not hitting the bowl, it's close enough.

Any ideas?

 

Try blowing compressed air back into the tank. Maybe plugged in the tank? And of course the obvious - fuel filter?
You said you have to open it up and clean the bowl evey six months. What do you clean out?
Are you running fuel filter? Is there a screen where the fuel line bolts to the carb?
Sounds to me like crap from the tank / lines.
As an old air-cooled VW guy also, have more than a few times stumbled across old VW's stranded on the side of the road starved for fuel. Take off the fuel line, blow back toward the tank as hard as you can till it breathes more freely, and they would be off and running (at least for a while till the tank screen plugged again!)

 

Thanks for the idea- I will try that out.

When I've opened it up in the past, I generally just pull the top (air horn) off, take the float needle and main jet out, and spray out the inlet as well as all the holes that fuel flows through.

I do have a fuel filter, on the tank side of the pump. It is the clear plastic variety, and it looks clean. There is not a filter screen on the inlet, and I was surprised to find that there wasn't one in the kit I bought. The truck doesn't see many miles in the warmer months, and nothing really comes out of the inlet area when I clean it, so I've assumed that it was more of a varnish issue than contaminants. I suppose it wouldn't hurt to replace the rubber fuel lines too, I've just been so focused on the carb...

 

Those filters are meant to be on the pressure side of the pump.

Used on the suction side, with just a little trash in it, the filter element can collapse.

 

It doesn't have the big filter made onto the fuel pump?

 

No, it doesn't have the filter style pump, although I recently got a spare pump that is. From what I can tell, someone pulled a lot of parts off another vehicle with a straight six to put this thing together, or replaced the motor all as one, but I don't know why you'd drop in a new 240 if you were going to the trouble to pull the motor.

I guess I will replace the rubber fuel lines and pump this weekend, and blow out the hard lines. I can get rid of the in-line filter at that point, since it's in the wrong place. Is there a screen or anything in the tank/sending unit that I should deal with while I've got the fuel lines all off?

 

There's a nylon strainer in there. If it's deteriorated or missing, you can get a new one from Ford.