Wants to stall after freeway

[WACO]

So I spent all kinds of time fiddling with the carb on this truck (2bbl) and the 318 ran so smooth and great it was redicules. Today, I moved the truck up to where I now live. It ran fine on the freeway, but when I pulled off it idled horribly and coughed a bunch of black exhaust. Popped it in nuetral and cleared it out. Then for the next few stop lights it was hard to keep running. Then, all of a sudden, it was like a switch got flipped and it went to running fine again. Anyone have any ideas? I am going to use this truck for a commuter for the next week (~50 miles a day) and I dont want the thing acting up on me in Seattle rush hour traffic!

Thanks

[DiverDwnPowrRam]

stuck or binding choke but maybe not seeing as how the freeway driving was with an already warmed up engine

[GHS]

Float adjustment, or sticking float in the carb?

I've had that symptom with a rebuilt carb that had the float set too high.

[Speed Dragon]

Sounds like a piece of dirt got stuck in the needle and seat, holding the float open a bit. Put a new fuel filter on it.

[WACO]

Thanks for the replies,

The choke I converted to manual - the vacume/heat spring wasn't working anymore, so the choke *should* be open as long as the knob is pushed in

The fuel filter is brand new, and clear. I am wondering if the floats may still be too high. I adjusted them down to an RCH below the 1/4" the instructions called for, but on my way out of the harbor yesterday (truck was still somewhat cold), comming to a stop on a steep hill the truck acted really flooded. The thing is, it has ran great until then.

Not much of a problem driving into work this morning. Maybe it was a fluke of some kind?

[bherder]

I'm kinda' leaning towards what Speed said.... I've had my float stick open and closed at times (Of course this was when it was 20 below outside) and a rap with a screwdriver handle on the carb fixed it right up... Could be just a fluke thing. On the other hand you might want to pull the top of the carb off and make sure the float isn't hanging somehow and double check yourself on the float level....

[acton mike]

sounds like carb icing

we do not see it much with F/I vehicles but with carbs it can happen in winter or summer

carbs have a system to bring heat to the carb and you need to make sure it works

fast moving air and evaporating gasoline create cold temperatures and any moisture will ice up the carb
pilots of piston aircraft with carbs and control carb heat to prevent this

automobile engines have a system that is supposed to take care of it

look into this because once the ice melts away the engine will run smooth as a baby's bum

[Speed Dragon]

Could be carb icing, doesn't quite sound like it but possible. I think it sounds more like the float level is too high, as he said, since it seems to do it under braking and on hills. Could be a bad needle and seat to, though unlikely.

[76D100]

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


-Has your truck failed to do anything on start up?
-Has your truck started kind of barely engaged the starter when you turn the key?
-Has your truck ran great on the highway and streets except for idleing at lights and signs?

This fix could be for YOU! (and me too...)

Look in to your battery cables. seriousley look in to them. My truck did EXACTLEY that 300km form where I was coming from and 700 from home... They were corroded inside and a little on the out. Even thoe I cleaned my terminals a few weeks ago all the corrosion was in the wire and where it connected to the terminal. If its 30 years old its probibaly a little sketchy. Try replacing it (theyre cheep)

[Delray Dude]

I vote for stuck needle in carb too.....

especially if it's been freshly rebuilt, they sometimes "hang" till they get worn in some.....kinda PITA, but nothing a good ol' beating implement like a screwdriver won't fix and a little time.

[Delray Dude]

another thought - I know you said the filter is clean - but there could be corrosion from the line AFTER the filter as well, coulda had a blob of gunk dislodge from it (assuming an old line) while cruising on the freeway and found it's way to the float and held it open....

[WACO]

Thanks for the replies, all excellent ideas! The truck ran great yesterday for my commute and so far it has today, so maybe it was a fluke or a sticking needle or something.

Carb ice is a possibility, it has the factory air cleaner, but the heat pipe broke off. When I was working on it last month, and the engine was cold I saw ice buildng up on the outside of the carb, and simultaniously the engine would start chugging down, but once I gave it some RPMs for a few seconds it would melt away and run smooth. Sunday was a very wet and humid day, I guess it is possible carb ice happened while cruising at 2500 RPM. I am a pilot and definately have experience with carb ice while taxiing around on the ground.

Also, the battery terminals are clean, but the wires definately look like they could be replaced, and I have had it not do anything when I turned the key. When that happened I jumped the terminals on the box on the fender with a pair of pliers and got it to turn over. After that the key has worked.

Well the truck has ran fine so far, hoping it will keep doing so until I get my Jeep back on the road and have some time to continue working on the truck.

[76D100]

If the cables look like they could defenetley be replaced and you have had problems before.

I vote change the cables. They will give you problems again if they have before.

[WACO]

Yeah, looks like I have another weekend project. At least with the truck there is a total of about 3 wires lol.

Ok the truck did it again on me this morning going to work - I think it is "wet blooded"! It was raining again this morning (mon and tues were dry), and sure enough for the first couple of stop lights after the freeway I had to powerbrake or pop it into nuetral to keep it running. After 2-3 stoplights it ran fine again. It seems like it doesn't like the rain!

[76D100]

Name me one mopar that does like the rain... Your problem is an electrical connection from your battery. When you drive its working off the altinator which is fine at say 1000 rpm however when you drop too low for the charge to run the truck...

Im sure you get the idea.

[bherder]

Uhhhh... Actually, I've never had any of the Mopars I've ever owned give me probs in the rain... Really! :D

Yeah, the older ones have their probs, (Non-rain related) but once you make them 'right', they're as good as gold.. ;)

Hell, my ol' 79' PW was one of the few things that got me to/from work this winter with 8+" of snow outside... ;)

[76D100]

8"+ of snow isn't quite monsoon rain. Hell, my truck has started and ran fine compared to other newer vehicles considering the icing carb issues in -45 winter.

[bherder]

8"+ of snow isn't quite monsoon rain.

True, but water falls off and dries.... Snow builds up and sticks and stays there .... you know what I mean ;)

Hell, my truck has started and ran fine compared to other newer vehicles considering the icing carb issues in -45 winter.

Heh heh heh .... I've had 'new' rigs with the computers/FI/you-name-it that wouldn't start when it's that cold.... As long as I keep my antique PW block heater plugged in, it fires up every time :D

But honestly, if I ever had any water related probs with any Mopar I've ever owned, it was with the big-blocks where the dist was right up front and would get sprayed. I doubt they make it anymore, but back then, we would get this stuff from 'McKay' called 'Ignition Dry' ... You'd spray your whole dist with it, and it pretty much made it water-proof. Worked very well....

[doodlebug]

I doubt they make it anymore, but back then, we would get this stuff from 'McKay' called 'Ignition Dry' ... You'd spray your whole dist with it, and it pretty much made it water-proof. Worked very well....[/COLOR]
Now it's called WD-40. :D

[bherder]

Heh heh ... You're probably right ;)

I 'think' this stuff had alcohol in it though ... It sure SMELLED like it.....
Maybe that was the 'magic' ingredient... :D