Hey Friends,

Picked up an 83 SR5 4x4 a few days ago. Super stoked but she won't idle. I'm pretty well skilled at car repair but this is my first carb vehicle. Need some help from the pros!

I dumped gas into the carb and can see gas level near the top in the carb window. I give the primer lever a few pulses for a few good sprays of gas. Turn the key and she roars to life immediately but will only stay running if I keep my foot on the gas. If I let off, she dies.

I have verified that my fuel pump is working using an external gas tank and clear hose directly between tank and pump.

Thoughts? Thanks all!

 

Sounds a lot like the same issue I was experiencing. Probably a vacuum leak, check all your lines especially if they’re old and cracked.

i wrote up a post about it https://www.yotatech.com/forums/f114...-lines-315358/

 

Thanks for the reply Chowder. I’m currently cleaning the hell out of the carb and will double check vacuum next. I need to try to pass CA smog anyway so I’ll need to check connections. Thanks!

 

Vacuum leaks are great to check for, but if the truck has been sitting for any length of time, or Ethanol-gas has been run thru it before, it could be a clogged idle circuit. Those passages are tiny & it only takes a very small amount of "crud" or some rubber particles that the Ethanol degraded from the old fuel lines to plug them up.

Good on the clean-out but here's a tip. Remove the Idle Shutoff Solenoid & the Idle Mixture Screw. Be sure to turn the screw to the right FIRST slowly & count the number of turns until lightly seated, so you can put it back later in the correct position/setting. Spray a good amount of carb cleaner in both these ports. Repeat as needed. This usually helps clear out any blockages in the idle passages. If you can also get some light compressed air in there so much the better, but take it easy doing this. No need to put 80 PSI in it; you can blow out gaskets & seals that way. I've gotten some carb'ed vehicles sitting up to 20 years going doing this idle circuit cleanout.

 

Thanks for the reply Swords. Yup. I’ve cleaned ever orifice of this carb. Good call. Re-installing in the truck today.

does anyone know if the shutoff solenoid is supposed to physically move or just click when 12v applied?

 

I'm pretty sure the solenoid has a plunger that moves into the orifice it's mounted over when the +12VDC on it is removed. IOW: When the key is on, allowing the engine to run, the plunger is withdrawn from the carb, allowing fuel to flow into the carb, and when the key isn't in ON, IE: the engine should shut down, the plunger is inserted into the carb by spring tension, blocking fuel flow. Prevents "dieseling", or the engine idling on after the key's shut off.

Does that help at all?
Pat☺

 

That does help a lot and that would explain why my engine shut off currently sucks. My solenoid does not move.

Fortunately it seems to be stuck open because after a good cleaning the truck now idles!

Thanks everyone!