Carb Issue

Joined
May 4, 2017
Messages
140
Location
Florence, South Carolina
Starts fine with choke and idles easily. After I start driving there is a hesitation as I accelerate and it feels like it is not getting fuel. If I push harder on the gas she'll finally open up and go on down the road.
If I leave the truck in the garage you can smell the gas like there might be a leak.
I had a mechanic check it out, he said the timing was good and that the linkage to the carb was good and suggested I have the carb rebuilt and that should fix the issue.
Would love to hear y'alls recommendations.
 
Joined
Nov 23, 2012
Messages
1,013
Location
San Diego
the choke will rich up your mixture so if it doesn't run proper you maybe too lean. you might also have an issue with the off idle setting. The primer not squirting enough fuel to match the incoming air increase. I had nearly the same issue and it ended up being crud in one of the bowls. I am not a carb expert, and i have zero experience with stock pig carbs, so, yeah. good luck.
 

PabloCruise

 
 
Joined
Jun 3, 2004
Messages
17,940
Location
Northern Colorado
Fuel smell in the garage could be a few things...

Is your evap system hooked up correctly from tank to charcoal can to carb?

There is a one-way valve near the vapor separator in your DS quarter panel. Mine was cracked and put lots of vapors inside the passenger compartment of my Pig.

Last - my gas tank had a crack on the top. The tank had visible stains on the side where the fuel had wet the side of the tank. It sounds like others have had problems with cracks as well.

Pictures of all the above in my build thread.
 
Joined
Aug 26, 2009
Messages
12,494
Location
down in a hole.
carbs are mysterious creatures with as many moving parts as an engine long block, but very simple in nature. plain and simply, they suck. I mean that's what they do; aaaand that can suck sometimes...search:
okie rebuild;
accelerator pump;
Pin_head carb rebuild videos...

couple tricks to try:
with a welding gloved hand and a piece of flat cardboard big enough to cover the air horn, fire the rig up, pull the choke out and run it at high idle without the air cleaner on and choke it out with the cardboard and gloved hand. if it doesn't have any intake leaks, it'll speed up just a bit then die. If it bogs down but keeps chugging on, then you have air getting in downstream of the airhorn, which is bad, unkay? that would mean you need to find the source of the leak, fix it, and see what you have to do there to get things back in shape...So let's pretend that it speeds up and dies...do this like 3 or 4 times. If the Okie rebuild doesn't fix it, while the air cleaner is off, and the engine off- in fact, do this one after the engine cools down to be extra safe- look down the primary barrel- on the passenger side- and actuate the carb linkage fully and watch for a steady stream of fuel from the accelerator pump. if it is weak or non existent, this could be your issue, but it would best be fixed by doing a full rebuild. they are not hard, just tedious, dirty, and detailed.
 
Joined
Aug 26, 2009
Messages
12,494
Location
down in a hole.
you can also remove the air cleaner, pull the choke, fire the rig up, then put the welding glove on and take up the piece of cardboard- it may be awkward trying to do all those things the wrong way round with one hand gloved and clutching a piece of cardboard...YMMV; HTH
 
Joined
Nov 23, 2012
Messages
1,013
Location
San Diego
When people have car troubles i usually say "lift off the radiator cap and slide a new car under it" but this is a pig so that wont cure anything. I had carb issues for a while and even when it was running well, as soon as i did anything "fun" it would crap the bed. Thats why i have EFI now. it is not a carb, so it is not a %$%^&* piece of @#^%.
 
Joined
May 4, 2017
Messages
140
Location
Florence, South Carolina
carbs are mysterious creatures with as many moving parts as an engine long block, but very simple in nature. plain and simply, they suck. I mean that's what they do; aaaand that can suck sometimes...search:
okie rebuild;
accelerator pump;
Pin_head carb rebuild videos...

couple tricks to try:
with a welding gloved hand and a piece of flat cardboard big enough to cover the air horn, fire the rig up, pull the choke out and run it at high idle without the air cleaner on and choke it out with the cardboard and gloved hand. if it doesn't have any intake leaks, it'll speed up just a bit then die. If it bogs down but keeps chugging on, then you have air getting in downstream of the airhorn, which is bad, unkay? that would mean you need to find the source of the leak, fix it, and see what you have to do there to get things back in shape...So let's pretend that it speeds up and dies...do this like 3 or 4 times. If the Okie rebuild doesn't fix it, while the air cleaner is off, and the engine off- in fact, do this one after the engine cools down to be extra safe- look down the primary barrel- on the passenger side- and actuate the carb linkage fully and watch for a steady stream of fuel from the accelerator pump. if it is weak or non existent, this could be your issue, but it would best be fixed by doing a full rebuild. they are not hard, just tedious, dirty, and detailed.
Hi Lamb, tried your cardboard technique and the engine choked out, so that means no issues with air down stream.
I did finally decide that the truck doesn't get down the road until I push hard enough on the pedal to engage the emissions overdrive switch located under the gas. Thoughts?
 
Joined
Aug 26, 2009
Messages
12,494
Location
down in a hole.
much less than half under load could make it difficult for the whole "sucking" thing to happen, which would [suck] while not doing what you want it too...too much over half could have the opposite effect while maintaining an eerily similar, non-desirable result- another reason the whole "sucking" thing [sucks]...you might could benefit from pulling the air horn and resetting the float to maintain a half--17/32 full bowl... but again, verify the accel pump before fiddling much more...
 
Joined
Aug 26, 2009
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if this is a stock 77 carb with stock emission systems components, there could be several hundred hidden things happening...As Bob asked, this is a factory carb from a 77? are you currently running any of the original smog gear? sounds a bit like an EGR stutter now that I've plugged that possibility back into the mix...have we ruled that out yet?
 
Joined
Aug 26, 2009
Messages
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down in a hole.
Oh s***... I had zero luck finding the whole setup that would get my CA77 thru smog- ended up going to fj60 everything including cat and comp... this next piece is very important as to what I might recommend next...

Do you need it to maintain your stock smog-ability for any reason ever whatsoever? Take your time in considering.,.
 
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