Truck is stalling out...Do I need a new carb?

[spoalowairchamp]

Anybody have any ideas about this new problem I'm running into. My truck will just cut off when I'm driving leaving me steeringless and brakeless. When it comes to a complete stop I can crank it right back up and start again. I took it to the shop and the mechanic hopped up the idle a tad but said I'd need a new carb soon. I thought maybe it was a clogged fuel filter.

It had been running well lately with the exception of the idle dropping when the truck was still and black smoke coming out of the pipes. I started running Lucas fuel treatment and that seemed to help a bit. The other thing is if I jam the gas pedal to the floor it sputters then catches up accelerating slower that it seems it should.

Sorry for not putting this earlier. My truck is a 1982 C-10 - 305 - Auto Trans and I believe a 4brl carb

[olblue81]

The "need a new carb soon" thing seems like someone is out for your $ but I don't know the whole story probably. 2 weeks ago my 81 was doing what yours did. Mine would only run if I had my foot in it. As soon as I tried to let it idle, it would puke black smoke out the tailpipes and die.

You probably have a stuck needle and seat in the Qjet. If you're lucky, you can start the motor, pull the fuel line that goes from the fuel tank to the fuel pump off and let it run the carb dry and maybe that will suck the crap off the needle and seat.

If you're not lucky, take the fuel line off the base of the carb and spray carb cleaner in there. A lot, not just a squirt or two. That would be the 30 second carb job.

If you're really not lucky (like I was) you have to undo all the screws and bolts on the top of the carb and carefully lift the top off the carb and try not to wreck the gasket while doing it. (The choke linkage is tricky and if you're not mechanically inclined then this operation is best left to a pro.) Then spray carb cleaner between the carb body and the front of the float (where the needle and seat are located) and that will probably flush the kookamonga off them.

If none of those work, then it's time for a pro to disassemble, clean and reassemble.

To test if your Qjet is wore out, spray something flammable (like carb cleaner) where the throttle shafts go into the carb base and see if the rpm pics up. To see if the product will pick up the rpm, just spray it in the carb throat first. If it doesn't pick up rpm then grab something else. A lot of products have gone to non-flammable formulas. If the rpms pick up when sprayed on the throttle shaft, then the carb needs to be disassembled and a bushing kit installed in the carb body. Best left to a pro. I found a shop to do mine.

A little diagnosis could prevent spending a bunch of cash on a new carb.

[spoalowairchamp]

[spoalowairchamp]

Oldblue81,
Is the fuel line on the base of the carb the (in the top most picture) the metal inline (under the topmost rubber line) towards the front left? If so is that metal line flexible when I pull it off?
Thanks again for your or anyone else's help in advance!

[jd74c-10]

q-jet carbs are known for the main jet plugs dripping fuel inside the carb and causing them to flood the engine with gas. buy a carb kit and rebuild it. the kits are anywhere from 20.00 to 45.00 depending on the model number of your carb. if you don't think you can rebuild it ,find a good local mechanic that knows the right way to build it.otherwise you will end up with more problems. the replacement carbs from most autoparts stores are just rebuilt used carbs just like yours. you can pay at least $300.00 at autozone for a rebuilt or around $100,00 to have yours rebuilt.

[3r!c84]

the filter is right where the fuel line go's into the carb.you unscrew that and its in there

[olblue81]

In the bottom photo, the line closest to the frame rail should be the line coming from the fuel tank. When mine acted up, I pulled it off the pump and folded it in half to keep fuel from puking out and waited for the engine to stall. Should take 30 seconds or so. Sometimes you get lucky and that will pull the junk off the needle and seat. Sometimes you don't.

As mentioned above, the fuel filter is in the front of the carb behind the large fitting. If you look close on the front of the carb under that vacuum line it will say filter. It's a bronze filter and I like to chuck those and replace them with an inline filter (Fram G2 or G3 depending on whether you have a 5/16 or 3/8 fuel line). I put the filter down by the frame rail on the hose coming from the tank.

[karl]

Ya check the easy stuff 1st like the filter(s), lines, pump. You can get a fuel pump/ vacuum tester pretty cheap at Harbor Frieght. Theres a pressure check and a volume check. Look in the Haynes manual or the likes.

[spoalowairchamp]

Originally Posted by olblue81

In the bottom photo, the line closest to the frame rail should be the line coming from the fuel tank. When mine acted up, I pulled it off the pump and folded it in half to keep fuel from puking out and waited for the engine to stall. Should take 30 seconds or so. Sometimes you get lucky and that will pull the junk off the needle and seat. Sometimes you don't.

As mentioned above, the fuel filter is in the front of the carb behind the large fitting. If you look close on the front of the carb under that vacuum line it will say filter. It's a bronze filter and I like to chuck those and replace them with an inline filter (Fram G2 or G3 depending on whether you have a 5/16 or 3/8 fuel line). I put the filter down by the frame rail on the hose coming from the tank.

OlBlue81,
Thanks for the tip. After getting under the truck I see two lines going into the fuel pump. The one closest to the frame is the larger one. It looks as if both of those lines are attached to metal lines going back towards the gas tank. Is that second smaller line a vaccuum line? Thanks so much for your help!