2150a troubles

[robert.humm]

yes the hose does fit tightly.. probably is fuel line haha. the choke works properly as well. i adjusted my float level & it seems to have stopped the backfiring. but the choke pull off seems to work only when it wants to. when it doesnt, i have to prop the valve open a hair to get it started.

 

[kimcrwbr1]

Yea they can be a pain at times on the back of that pulldown is a cap and inside is the adjust screw or at least there was one on the one i had that the nipple broke off of in shipping. if the vacuum pot is good the adjust screw on the cam in center behind the thermostat controls how far it closes i think it ia a 1/4 inch screw you just gotta play with it it uses gravity it coul be binding somewhere. did you get the idle air dialed in

 

[robert.humm]

well lol.. kind of. it doesn't really seem to make much difference no matter how i adjust it. idk if something else should be adjusted first? but i ended up just setting them at 1 1/2 turns out & leaving it. i had it adjusted real well, then i adjusted the choke & fast idle.. then it seemed like i couldnt get the mixture set back right. so idk lol.

 

[kimcrwbr1]

did you unplug the the feedback solenoid on the back of the carb and try that with the computer controlling the advance I could not get mine to run decent it ran best with my idle screws 3 1/2 to 4 turns out to idle and run good but fuel mileage sucked until I did the duraspark conversion and put new valve guide seals in it. Have you checked the egr for leaks if you apply vacuum at an idle it should stop the engine you can put your finger up under the valve and tell if it is pulling it open when you apply vacuum. mine was plugged and not working at all and you can just block it off with a plate to eliminate any leaks there.

 

[robert.humm]

no i did not unplug the solenoid, i guess i'll give that a try. the egr valve is brand new lol.. i bought it before i decided to duraspark the ignition. but that's pretty much the only "emission" vacuum line hooked up. should i should unplug it & block it off? i would just like it to run decent until i can swap the ignition over.

 

[kimcrwbr1]

did you have the air cleaner plugged in when you were adjusting it you can also try plugging everything in you have disconnect the battery for 15 minutes plug everything in then start it and try to adjust the carb just mess with it till you get the parts to do it right

 

[robert.humm]

i'll try that

 

[Hotrodlincoln]

The large 90° pipe coming off the front there is for the evap system, plug that up if you don't have anything connected to it.

That little nipple on the front there that sticks straight up. I forget exactly what that thing does, but I wanna say I connected mine to manifold vacuum and it made it run better. Or was it ported vacuum... I can't remember. Probably safest to plug it into ported vacuum first if you wanna play around with it.
Also check the voltage to the electric choke. It's probably getting like 7v, and it will work about 100 times better if it gets a full 12v.
Is the choke pull off plugged in? Can't tell in the pic.
There is a large vacuum tree on the manifold behind the carb. Check all the plugs on that for splits and cracks. If you ditch the computer controlled crap you can just remove that and put a 3/8" plug in there.

 

[kimcrwbr1]

the vacuum port on the front that pionts up turns off the accelerator pump when vacuum is applied you can cap it or just leave it my guess is the computer turns it off at higher rpm when the power valve is working

 

[robert.humm]

the choke pull off is hooked up, just a bad pic i guess haha. but it only works when it feels like it. if i go outside right now & try to fire it up, the pull off may or may not engage. then 10min later.. it may do the opposite. it's pissing me off lol. the pump relief valve is plugged off now.

 

[kimcrwbr1]

mine had a bad diaphram and the port on the carb is restricted with a real small hole going through the base. It makes a world of differense getting it working right for cold starts sounds like your real close tho. It needs to be fully open before you can adjust the idle air correct my feedback carb needed to be 3 1/2 to 4 turns out to run decent at an idle well GL

 

[litleblue]

You have 2 choices, 1st: repair the entire control system, 2nd: scrap the control system, duraspark the ignition and replace the carb with a non feed back type, or install a meetering block on the feedback carb you have.

I really think the reason you are having problems is the computor is running in limp home mode. Limp home mode is a default that Ford programmed into these computers if a serious problem developed with the computer or the critical sensors. By your pictures I see one such sensor missing, the DC Idle Speed Control Servo, should be bolted to the driver side of the carb. This device sets the curb idle (800 to 900 RPM) with the input of the throttle position and engine coolant temp sensor as well as other sensors. When the sensors are not working or missing the computer turns off data collection to manage the engine and defaluts to programed values. This includes the spark advance. The limp mode values will allow the engine to run with a significant decrease in performance and milage.

The little nipple that is in front of the carb is the accelerator pump enrichment valve. That device should be connected to one of the solinoids that are on the passenger side of the engine compartment by a blue vacuum tube. While the engine is warming up the the solinoid allows vacuum to be applied to the device on the front of the carb. This vacuum valve opens an additional port to the accelerator pump allowing more fuel to be delivered during cold acceleration. If it isn't working the truck will stumble when starting from a dead stop when cold.

Repairing the control system properly, or durasparking with the (proper mods to the feedback carb, or replacment of the carb with non feedback), and a stock axle and tire combination, the truck should get about 22 to 27 MPG on the highway driving between 55 and 65 MPH.

 

[robert.humm]

i see. i gues im gonna go ahead & do the swap.. ive just been picking up the parts wherever i could find a deal.. but i guess ill just go ahead & get it done now.

 

[kimcrwbr1]

You will be happy you did, just make sure your on top dead center on the compression stroke when you change the distributor and line the rotor up with #1 on the cap plug the harness in and connect the green wire to neg on the coil thats all there is to it if your doing the duraspark. the wires from the ignition are coded different but they are correct when you plug in the oval 2 wire GL Kim

 

[happilymarried]

I know this is a slightly older post, but if someone is still watching this, I could definitely use a little help with my Motorcraft 2150 carb.

It was leaking like crazy, so I just rebuilt it (stopped all the leaks) but am really having a tough time getting it perfectly dialed in. My biggest problems are a lot of hesitation when it's cold (really have to have give it a ton of gas from a dead stop for the first few miles until it's totally warm), and it idles incredibly rough when cold. Second, the "DC Idle Speed Control Servo" does not seem to be working properly. I mean, it goes in and out and stuff, but I had to adjust the idle screw at the back of the throttle lever to keep it running, and now the servo doesn't even touch the lever most of the time.

I also wondered about the accelerator pump causing some of the problems with hesitation. When I rebuilt it, I wasn't sure which spring setup to use, so I just reproduced what I took out of it, but then I thought the instructions in the kit were telling me otherwise. Basically, I have a spring, the diaphragm, another spring c-clipped into place on the shaft on the front side of the diaphragm, then the cap and cover. This double spring set-up seemed weird to me, but it's what I pulled out of the carb when I took it apart. The thing that concerned me was that the instructions with the carb kit just showed spring-diaphragm-shaft-cap and cover, then there was a picture to the side with the second c-clipped spring with the caption "for automatic overdrive transmission only." I'm running the 5 spd, so should I have removed that second spring? Is this causing too much resistance and hurting the throttle response?

I definitely don't have the money for a duraspark conversion or anything like that...pretty much just trying to keep the thing alive for the next couple years while the wife and I clean up some debt and stuff. Any input would be GREATLY appreciated.

Thanks guys!