Well, I thought it was a cold-weather-only thing, as it was running
perfectly last Fall, but apparently, that's not the case.
To remind people, it's a carb'd 85, 302 auto, AOD. It's not a Holley.
It has an adjustment on the driver's side where the throttle
cable comes is also the adjustment for the automatic choke.
I can't seem to see the number at the front of the carb that
would tell me what model it is. Maybe I haven't looked carefully
enough, which is possible.
The problem? It won't idle. And it seems to run just a wee
bit rough.
There appears to be literally only one adjustment screw on the
whole carb, which is the above-mentioned screw that seems
to control the throttle, and in part, the auto choke.
Completely tune-up done, all filters, timing, plugs, you name it.
So, I'm confused. The only thing I can figure out is maybe the
fuel sucks, but 38 gallons is not something I want to throw away.
I did add a bit of Seafoam at one point, but since I changed out
the fuel filter, and that made no difference at all, I figure it's
not crap in the tank working it's way through.
The idle mixture adjustments for this carb(I am assuming it's a 2bbl 2150) are down low underneath the bowel on the front base of the carb. If it's never been rebuilt, then it has caps over the screws so you can't adjust it. If you find this is the case, then I would rebuild it. When you rebuild it, you have to chisel the metal away from the screws. I would also take the egr off, make a block off gasket, and stick it back on and see if it runs smoother. The egr may be leaking, and this would cause stalling and a rough idle.
Get a vacume gauge and check what its doing. A vac gauge is very usefull when used for diog. It will most likelly come with reading guidlines with pictures to help. Alot of manuals will have vac symptoms listed as well. A stuck EGR will cause what you list as symptoms , but a gasket leak , cracked or burnt valve my as well . So go alittle deeper into the research before to many hard parts or mods are made. Good luck. Oh and welcome - come back often - Tis a great site .
Gonna try and post a link to autozone.com; when I preview my posting everything
works but the HREFs look entirely bad. Regardless, it/they both take you to autozone.com
Since it was mentioned about the egr being under the carb(the plate that is), it reminded me that some people have had problems with the gasket burning out underneath the carb. This definitely would cause a rough idle.
OK, there is no EGR on the "front" (like, front of truck) side of carb
down low. On the passenger's side there's the fuel filter, and on the
driver's side there's the accelerator pump. That's it.
I did find the PCV valve and replaced that. No difference.
I found an electrical plug that wasn't plugged in, and needed to
be, that went into some kind of valve at the top and back of the
carb. Plugged that in, and no difference.
I also found the auto choke and adjusted that - there's a little
adjustable bolt on top. No difference, really.
Finally, I have found no adjustment screws, or even possible
places for adjusting a screw, on the front of the carb. They
must be around back, but I can't see back there at all well.
Again, the problem is that it simply won't idle. I believe that
it's just running way too rich. If I could find that adjustment,
I think I'd be a long way down the road now.
Well, the screws are apparently there, but almost impossible to find,
and certainly very difficult to see. Shew. Who designed this again?
I now need to find a screwdriver short enough to get in there. I'm
assuming it's a regular not a philips, right? Which way for more lean?
Clockwise or counter-clockwise?
I am wondering what screws you are looking at. In your first post you said the auto choke adjustment was on the driver's side, and a few posts later you said it was on the top. It's the large round black piece on the passenger side. By the way, the egr is in the rear area of the carb.
Like I said in my previous post, if this carb has never been rebuilt, the screws will be hidden, or if you can see them, they will have plastic limiter caps and you can't adjust them much anyway. Ford designed the carb so you could not adjust it because of emissions reasons. Now the carb is so old, it needs a rebuild, and during the rebuild, you can undo the Ford design so you can adjust it.
I have an 83' carbed 302 - more or less the same engine with an AOD.
Personally, I find that I need to make a small choke adjustment when hot weather sets in and another small adjustment when cold weather finally returns. If I don't, the truck will idle "funny" and will occasionally overheat (not much, but enough to notice - especially during the winter, denser air I guess).
Also, when I let a carbed vehicle sit more than a few weeks, especially if it was used regularly before that, I will buy a can of carb cleaner - follow the manufacturer's directions carefully as the stuff is kinda nasty to be around. Personally, I like Gunk products, but to each their own.
I would never recommend that you rebuild a carb, or replace any other part on a vehicle for that matter, without knowing exactly what the problem is first. Been there & done it, it gets expensive quick cause I usually guess wrong.
The last time I worked on the carb for this truck, I followed this particular guy's instructions to the letter: International Full Size Jeep Association
Yes, they are for a jeep. Yes, this guide will work. No, I have never owned a jeep.
The adjustments on the driver's side (next to your cruise control cable) in front of your throttle kicker (aka Dashpot) is your idle RPM adjustment. Behind the dashpot is a screw running through a bracket, this is the kickdown adjustment. This general area also should contain your fast idle adjustment (a screw that looks like it is going into the base of the carb on the back driver's side at an angle from the firewall down into the block). These are easy things to change as is your fast idle adjustment (choke side). Note that since I tried to do that from memory, there could be something wrong or left out - corrections will not be resented. The idle mixture (those screws under the fuel filter and accelerator pump) typically do not need adjustment. If they do, my preferred method is with a very, very long screwdriver (i.e. about 18 - 24") with a small diameter shaft. You should have exactly one position on either side of the engine that will give you a good angle and a straight approach to the idle mixture screws and using a long carb screwdriver is the easiest way that I've found.
Whew, that was a long post to say "Try a longer screwdriver" - sorry.
Best of luck.
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