'83 intermittent rough idle/stalling

[XRO]

I have an ’83 Jimmy, originally came with a 305 but when I bought it the motor had been swapped to a 350 with Edelbrock manifold and carburetor. I’ve owned it for three years and for the most part it has always run good. It does have newer plugs/wires/cap/rotor/fuel filter. Takes a little cranking after it has sat for a week to get fuel to the carb, but the fuel pressure was tested and checked out last summer. Been running well this Spring after I got it out storage but has randomly and intermittently loading up and stalling (or wanting to) at stop lights. Doesn’t seem to matter if the motor is hot or cold. I can always re-start but it takes a lot of throttle and then I have to clean it out a little by revving. To me it feels almost like too rich of a condition rather than too lean, but I’m not sure. I restarted it after it sat for several hours yesterday and it was doing the same thing, had to rev it and clean it out and it went away –I did check to make sure the choke wasn’t stuck shut, which it wasn’t, but there was a bunch of gas on the outside of the carburetor – makes me extremely nervous – I got it home and haven’t had time to look at it since. I did put SeaFoam in the tank last year and before putting it in storage and I did start it up ~once per month of the winter. I also poured a container of Seam Foam through the carb a couple weeks ago. One other thing I will add is that although I don’t see it smoking much it does seem to smell like it is burning oil more this year.
I am not that experienced of a mechanic so was hoping someone could point a few things out to check before I have to take it in and pay someone to trouble shoot
Thanks in advance for any input

 

[76k5blazerr]

I would either rebuild your carb or look into getting it done by someone. I rebuilt my edelbrock 1406 a while back because I was having the same problem as you. Edelbrock carbs are really pretty simple to rebuild yourself. Also when you do it, replace your inline fuel filter in the gas line, and if for some reason you don't have one, get one.

 

[1-ton]

Edelbrock carburators are performance carbs, which are good at flowing fuel, but not metering it well. The first problem you are having is "fuel drain back". When your truck sits for a while the fuel is draining back into the fuel tank, which causes you to have to crank the engine starter motor for a longer time, in order for the fuel pump to bring fuel back up to the carburator.

The second problem is probobly loosing fuel pressure. when you come to a stop, turn a corner it excerts G-forces on the vehicle, or slow speed RPM's. These conditions can cause a mechanical fuel pump not to deliver the proper feul pressure to the carb.

There could be other problems as well, such as vacuum leaks, but most of what you describe are typical Edelbrock carb problems, which can be solved with an electric fuel pump, and an inline fuel pressure regulator between the fuel pump and the carb, and another between the fuel tank and fuel pump. This will keep fuel to the pump and carb under all conditions. pLUS THE CARB MAY NEED A REBUILD IF IT HAS A LOT OF MILES ON IT.

 

[diesel4me]

An oil & filter change would be a must if you suspect it has been running rich or has flooded ,gas will get in the oil and dilute it and it'll cause excessive friction,wear,and can make it burn oil,being thinned out more..

It might have a float that developed a pinhole after sitting and its sinking,causing it to flood some..that would account for the rough idle and stalling...Edelbrock carbs are clones of the old Carter AFB,probably one of the simplest 4 barrels to work on...

 

[XRO]

Looks like I should rebuild the carb regardless. I bought this truck at an auction 3 years ago and it had been sitting for at least a year. I'm gonna say someone had a spare motor, carb, tranny, t-case, etc laying around in there barn and scrapped this together. Wish I had more history on it, but it is what it is. I think i can handle the rebuild, tuning will be another thing... will cross that bridge when I come to it...

I did just change the oil and filter a couple weeks ago.