I had posted this in the general forum, but this posting should really be in the carburetion section, so I'm posting it here instead and I apologize for the double posts.

Specs on truck:

1978 Ford F150 Custom
2wd
8 Cylinder 5.8 liter
2150 Motorcraft 2 barrel carb
Automatic

Long story short, did a rebuild on my carb. Didn't know anything about trucks three weeks ago, but learning quick. I followed the 2150 rebuild instructions on "therangerstation" forum, just for reference. I now realize I have messed up a bunch of the adjustments, as I didn't know what I was doing. Fairly confident I did the rebuild right....disassemble, soak all metal in carb cleaner over night, reassemble with carb kit,ect...I posted this somewhere else, so lets assume I did that right, so I'm not double posting again. Below, I posted observations of what I now realize I messed up, so lets go with the understanding that those adjustments are now obsolete and I'm gonna redo everything. I guess I'm just posting to get 1 or 2 feedbacks or any other suggestions in case I am doing something right or it sounds like I still don't grasp stuff.

Sorry it took so long to get back to this posting, I've been messing with the truck for two days. I managed to get it started (with the help of a REALLY nice guy I met at the auto parts store), but it stalled about a block from my house after only driving it for a few minutes and it took me half of a day to get it started again and get it back home.

Here is what I have done with regards to adjusting the carb. I don't think I knew what I was doing, I'm learning, but need a double check to make sure I understand all the screw adjustments. I followed the general tuning instructions on "therangerstatioin.com" rebuild site, but when I did the original adjustments I didn't realize there were spec sheets in my rebuild kit and didn't understand I should use them, SOOO I'm gonna have to start over from scratch. Just for reference though, here is what I DID do.

Carb off the truck - put choke cover on with spring between the fork and turn "rich" until choke plate closes. Didn't have a vaccum pump, so manually pushed in the choke pull off and made adjustments so choke plate had 1/8 inch space when choke was pushed in. This seemed to vary slightly by how I pushed it in, but not by much.

Carb of the truck - I set the fast idle speed so the screw was against the "V" notch. Not sure if I did it right though, because in order for it to go into the notch, I had to screw the screw almost all the way in.

Carb off the truck - the choke over travel lever I couldn't figure out and I'm pretty positive that is part of the problem. I just re-read the rebuild instructions on the rangerstation.com forum again and I THINK I FINALLY know how to adjust it now. But just to be sure...turn choke cap to rich or until choke plate closes, get the "carb tool"(which I DIDN"T have) and refer to specs on rebuild sheet and adjust the opening of the plate by screwing in or out.

Didn't do this - didn't do the choke plate pull down adjustment either. AGAIN, just referred to that rebuild site and the instructions listed there. I think it took me until JUST now, between fiddling with the truck and learning correct terminology and what each parts does to understand the instructions on that rebuild forum and understand what I need to do. I couldn't understand why every time I unscrewed the choke plate pull down rod that the gap in the choke plate settings changed.

Carb off the truck - recorded how many turns the two front idle screws were at when I disassembled for the rebuild and reinstalled those screws again to those numbers. I was trying to get the truck started later on, so screwed them in all the way till lightly seated, then backed out 1 1/2 turn.

Carb of the truck - after rebuild, I put the original float back on and that might have been part of the problem as well. I adjusted float /(dry /measurement) from top of float to top of bowl to 7/16. I didn't know how to adjust the tang properly at that time, so I was kinda pushing on the needle and think I ended up damaging it, because the truck only finally started after I put the ORIGINAL needle back in with the new seat. I now have a NEW float in there and I'm going to go buy another new paired needle and seat, just to be on the safe side.

I don't consider these last couple of days a wasted of time, because I have l have learned SOOOO much and I'm starting understand how the carb works. I have to start from scratch with all the adjustments, so I'm gonna take the carb off today, go get the carb measuring tool to do it right, get a new needle and seat, follow the recommended specs for my truck, and I'll report back either later on this evening (if I can get everything done) or tomorrow.

Sorry for the REALLLLY long posting. If someone would be willing to go over this and if any suggestions need to be made or it sounds like I'm not grasping a concept, please feel free to correct me. Again, I appreciate anyone willing to respond and I know your not obligated to share your knowledge, but I will listen to anything you have to say.

One final thing, rebuild spec sheet has 2 different setting for my year and model and I'm not sure which one to use....I think its for California emissions...don't have it in front of me at the moment, but I think one abbreviation said "AC" and the other I don't remember. Or maybe, those are for high altitude and non high altitude adjustments. If someone can let me know, that would be great!!

 

Here is a write-up I put together a long time ago that summarizes the steps necessary for all choke and fast idle related adjustments. Please read through this, and highlight which of your original questions are left over.

https://www.ford-trucks.com/forums/7...ml#post6422219

The general rule for idle mixture screws is to gently seat them, then back them out 1.5 to 2 turns each. It sounds like you've done that. The next step is to dial them in exactly using a vacuum gauge.

Here is some more information I put together about the choke, for your own edification: https://www.ford-trucks.com/forums/8...-answered.html

 

Need more help...here is the current update. Installed a new needle and seat. Adjusted float to 1/2 from top of bowl(dry adjustment), per rebuild spec sheet. Turned choke 90 degree rich, pushed in pull off lever, and used the choke pull off screw to adjust plate to a 1/8 opening.(closest fraction to spec sheet, once converted)

Adjusted needle and cam so when you open throttle, push in choke vacccum, and let off the throttle the needle sits approximately in the "V" on the cam. I fiddled with this for 1/2 an hour and got it as close as I could. Seems like when you release the throttle each time, the speed with which you release it affects where the needle lands in relation to the "V". Someone let me know if there is a more PRECISE way to do that adjustment. After that, I did NOT re-adjust the choke plate opening when the pull off vaccum is depressed. That might be part of my problem, so someone let me know if I was suppose to re-adjust that and I will go back and double check the directions.(FYI, choke was still 90 degree rich for this adjustment) I DIDN"T adjust the fast idle, cause the write up said you should do that when the truck is running. Right now, the fast idle is screwed almost completely in, so maybe that's part of the problem too. Adjusted choke to even, per spec sheet.


Poured a little less than 1/4 cup down her gullet and attempted to fire her up. I replaced the battery yesterday with 750cc, so turn over is quick and powerful with no issues. Truck started, but had to give gas the entire time, ran for maybe three or 4 seconds, then backfired and died as flames came shooting out the carb.

FYI, I have not adjusted curb idle either, but the curb idle is still at the same setting prior to carb rebuild, and the truck was running then and only had an accelerator pump leak.

I'm gonna start googling again and sifting the archives, will check back frequently for responses, so if someone can clue me in that would be great.

Thanks again fmc400, every time you post I get a little bit smarter and I now have a VERY rudimentary understanding of the adjustments.

Jennifer

 

Ohh..almost forgot, the idle mixture screws were turned out more than 1 1/2 from lightly seated when I attempted to fire her up. That was due to turning them out more when I had a friend come over the other night .We managed to get the truck running, but it only went a couple of blocks and then stalled, and we had a H*ll of a time getting it started up again to get it home. I'm gonna go seat them again and back out 1 1/2 and see if that makes any difference.

 

You bet, happy to help. My responses:

Why are you replacing the needle and seat after already having rebuilt the carburetor? Was something wrong with what came in the rebuild kit?

Are you using the hex screw in the plastic fast idle arm to make this adjustment? It should not be giving you much trouble.

If that's the case, then something must be binding, or the linkage is gummed up. Again, this should be a fairly trouble-free adjustment.

The procedure I linked to in my previous post is the procedure. It's essentially a user-friendly version of what's printed in any shop manual.

You don't have to go back and adjust the choke pulloff opening. It's set at the very beginning and remains constant so long as the set screw remains in place.

After the truck shuts off, carefully remove the air horn and see if you still have fuel in the bowl. Flames coming out of the carburetor throat is indicative of a severe lean condition - either you're trying to start a cold engine with the choke open, or you have a severe vacuum leak at the base of the carburetor. What did you end up doing for the base and spacer plate gaskets? You didn't use the paper-thin garbage in the rebuild kit, right?

Since ignition timing was presumably not changed since the last time the engine ran properly, timing can be eliminated for now.

 

Lightly seated the idle mixture screws, then backed out 1 1/2 turns.

Lets assume I have adjusted everything according to what fmc400 write up said and TEMPORARILY assume I did an okay job, except for adjusting curb idle screw and fast idle screw. FYI, fast idle screw is pretty much screwed in as far as it will go. I did after the rebuild...didn't know what the H*ll I was doing. Haven't touched curb idle screw since before rebuild. Starting point for choke before firing up is even, per rebuild spec sheet.

Tried firing up the truck 10 or 12 times, had to pour gas down her gullet(approx 1/4 cup or slightly less) every time, here is what happened.....


1-3 times - starts and runs for 2 or three seconds, but have to give gas the entire time and always ends up stalling, even while giving gas. Fireballs starting shooting out of carb when I rev almost every time after the second or third firing. I stopped after 10-12 tires, cause didn't wanna blow myself up When the engine runs, it sounds like it is running smoother, way smoother than I have ever heard before.

4-7 - started off with idle mixture screws at 1 1/2 and each time I go to fire up now, I back out the screws 1/4 turn, till I have backed out screws to 2 1/4 turn total. Each time I go 1/4 farther out, engine sounds smoother and stronger, even though it only lasts for couple of seconds before dying. At 2 1/4 turns, I'm noticing if I rev for a couple of seconds and let of gas, it will idle on its own, but only for 3-4 seconds before dying and carb producing a larger and larger fireball every time it dies.

8-10 - idle mixture screws still set at 2 1/4, I start fiddling with the choke which has been even till this point. Start at 1 rich, then 2 rich, then 3 rich. by the time I get to three rich, fireballs are reaching the underside of the hood in height, so I've had enough for now and need some advice. Funny thing is, when choke was at 1 and 2 rich, the idle got smoother still and engine was able to idle slightl longer before once again dying in a fireball spitting hiss.

Hoping someone on here can post some thoughts over night tonight. Once again, I did NOT re-adjust the choke plate opening width after I adjusted the cam and put the needle to "V" on the cam, so wondering if I should have done that. I'm noticing that the choke plate isn't closing to 1/8 now when the choke pull off arm is pushed in and in fact that measurement changed considerably after adjusting the cam.

Thank you again for any advice and anyone who takes the time to respond. I'm learning every time someone posts.

Jennifer

 

Thanks for responding, fmc400, I hoped you would see my post. I don't know how to highlight and paste previous words you or I have written, so sorry I can't do that like you did in your previous post.


To answer your questions....

1. I replaced the needle in the seat because I thought I had to and didn't know any better. This truck has potentially been sitting and seriously neglected for years, so I thought better safe than sorry. I used the one that came in the rebuild kit. Then I was dumb and trying to adjust the tang on the float, but didn't know what I was doing, and I think I damaged the carb kit needle, so I just went to my local carb shop today and bought another needle and seat.(just to be on the safe side)

2. Yep, I FINALLY figured out how to adjust the cam by using the fast idle linkage hex nut and lining up the needle with the "V". Problem is, I pull back the throttle, hold that and push in the choke pull off rod, then depending on how I release the throttle affects where the needle lands on or near the "V". If I just let the throttle release quickly out of my hands, it might land on the "V", but if I hold on to the throttle and guide it back down, I get an entire different placement of the needle in relation to the "V"

3. Good thing to know I don't have to adjust the choke pull off Thanks!!

4. There has been a problem with fuel getting into the bowl for several days now. In fact I probably should have mentioned it earlier, but I'm not sure fuel IS getting into the bowl. I opened up the choke plate, looked down at the tiny jets(not to be confused with the jet screws), and pulled back the throttle several times but there WASN"T any squirts of gas coming out. The fuel bowl always seems to be empty and the only time the truck fires up is after dumping fuel in the bowl or through the plate and then the truck runs for a few seconds and dies. On the flip side of that, I have had times where gas was gushing out the plate too. That, however, seems to be gone now that I have done the carb adjustments. Gas didn't gush out once when I kept trying to start her. I didn't have any of the carb settings right till now and didn't understand how to adjust them till now anyway, so my adjustments haven't been a waste and I have learned how to do them. I think you might be right and there is a fuel delivery problem which I didn't think to consider until now. I DIDN"T tear the "tit" when I installed it in the accelerator pump and the tail end IS sticking into the fuel bowl.

5. I DID use the gaskets that came with the kit, but I don't think this was the standard kit you get from Auto Zone. I got this kit from Mike's Carburetor shop online and I even called him up and asked him about the thick 1/4 thick gasket with the grommets in it and if that should be used on top of the egr valve plate, and he said yes. Maybe I'm wrong and please tell me if I am.....here is how it was put together.

1. Thin gasket put on base(gasket came in kit)
2. egr valve plate next
3. thick 1/4 black gasket with grommets on top of plate
4. second thin gasket (again, came from kit)
5. carburetor

bolt down, connect fuel line(I replaced the fuel filter today which was super plugger), also replaced fuel line hose between fuel line and fuel filter and clamped hose down with hose clamps.

FYI..I haven't gone through all the hoses under the engine. Some seem supple and barely worn and others are hard as a rock.


SOOO...please tell me if I didn't listen to you and I should have gotten another after market gasket, and which ones I should get. FYI, mike's carburetor shop has a video for my kit showing every gasket I got. You could check it out online in less than 2 mintues. Carburetor # D8PE- ATA

Thanks!!

Jennifer

 

Ohh...one last thing. The fast idle screw is screwed ALL the way in. I did that during the rebuild, thought I knew what I was doing with it, but obviously not. Could the fact that it is ALL the way in be causing a problem??

I don't know how to adjust that needle and is there a way to adjust it without having to have the truck running...say a base line or starting point, like the idle mixture needles.

I'll check back in tomorrow, going to pass out now.

Thank you, thank you, thank you!!!!!!

 

The only thing I can think of is that something is wrong with the linkage, such as slop or binding.

This is a serious problem that needs to be addressed first and foremost. Any fast idle or choke adjustments are worthless until you are actually regulating the amount of fuel in the bowl.

This is egregiously wrong. It does not match what I described in your previous thread. You're likely not getting any sort of proper seal at all, which would explain the backfiring. The thin gaskets from the kit must be avoided completely. The proper stacking is as follows, quoted from my post in your original thread:

My advice is only useful if you follow it. These instructions need to be followed to a tee; any deviation on your part makes all future troubleshooting moot.

The fast idle speed screw does not typically go all the way in. However, this is not a concern right now. You have way more serious issues and you need to pull the carburetor to address them.

What is "that needle" and what do you mean by "idle mixture needles" - the screws? Again, it doesn't matter right now, you have way more pressing issues to deal with.

 

I wasn't trying to "Deviat" from your instrucions. This is the second time you have yelled at me now, and I am DONE. I just maybe didn't understand. I thought these forums were supposed to be welcoming for beginners and experts alike. Never mind....I'll just be a lurker and try and figure it out on my own. Thanks for your input and I DO appreciate it, but I don't need to be made to feel like I am dumb or be yelled at or told that I am ignoring instructions when I'm just misunderstanding them. I didn't know squat about trucks 3 weeks ago, and apparently this is the wrong place to be posting newbie questions.

Goodbye.....

 

Goodness grief. I don't understand where this notion of "yelling at you" is coming from. I listed explicit instructions; when it became apparent that your end results differed from these instructions, I made it clear that it's imperative you align with my instructions before proceeding any further. If you're not open to receiving that level of feedback, then I'm not sure how or where you're going to find the answers you're looking for. I made no assumptions or assertions about why your end results differed from my instructions. In fact, I haven't expressed any sort of opinion at all.

I would have thought the fact that I've taken the time to parse through your multiple, highly verbose posts across multiple sections of this forum would be a sign that my sole motivation is (was) to help you work through your problem. I even said that I was happy to help earlier in this thread. It doesn't appear that you understand this to be the case. I feel like this has been a complete waste of my time. Best of luck I guess; I hope you are able to resolve your truck's issues.

 

I used this video to setup my choke.