I'm hoping to get some advice on a new/reman carb. 1984 300 i6 manual, no ac. I converted the ignition system back to the Duraspark II, so I replaced the dist, ignition coil, and ignition module. It's running great, but I get really bad gas mileage. I still have the feedback carb on there, with all the wiring disconnected and the computer has been removed. I'm looking at carbs for an '83 on RockAuto, and there are a few options including with or without AC, and with or without electric choke. My current carb doesn't have an electric choke, but it does have an electric choke assist (I think that is different?), which has never been hooked up since I bought the truck. I'm wondering if this Autoline reman will work. I think this is no electric choke or electric anything. I assume it has a vacuum advance port, but I don't see one. Does anyone know if this will be a good carb replacement for my Duraspark II setup?

https://www.rockauto.com/en/moreinfo...wKEOSMxA%3D%3D

 

Here is a good read....
https://www.ford-trucks.com/forums/1...-feedback.html

You really don't have to change to a non feedback carb, I never have.
Jim

 

Well I'm reading plenty of people who say it will run better with the proper carb, and I am indeed getting poor fuel economy. If I get the older carb I can hook up the vacuum advance which will help right? What mpg are you getting with your old feedback carb?

 

You should take the time to read the thread I posted above. Lots of good info and months of field testing.

Jim

 

If the electric assist is not connected AND your Hot Air choke tubes are rusted off (most are) the you are running with the choke ON all the time. Having the choke on all the time will give you bad gas mileage.
Jim

 

By 'choke ON', do you mean choked, with the plate closed? The choke is almost always open, letting air in.

 

Don't mean to speak for anyone, but choke off is more easily defined. That's with the choke plate fully open. Any deviation from off would be choke on to one degree or another to choke fully on with the plate closed.

I'm a big fan of eliminating all the electro gizmos and using a manual choke. Seems everything is on the table for automation. I've had carburated trucks with the thermal coil choke. That worked well. But my all time favorite is manual choke.

 

I'm in your camp. I want to remove as much electronic automation as possible. It looks like that AutoLine carb is purely mechanical, but maybe I'm wrong.

By manual choke, do you mean rigging up some kind of mechanical choke control in the cab?

 

Yup that is the guy you want. That is a non-emssions carb. If your ECU is disconnected and disabled you should replace the carb as you have no idea where the mixture stepper motor defaulted or stopped at when it was disconnected. Was it full rich (crap fuel mileage) of full lean (great fuel milage but a risk of burning valves) or is it somewhere in-between.
If you disable the feedback the system you change the carb simple as that.

The Autoline 6077 carb will have a port for the vac adance See first pic below . Your feedback carb also has a port in a similar location you can use for the vac advance in the interim.

Your feedback carb should not have any heat riser/stove for the choke control this is good news as you have no need to install a heat riser but you will have to make a simple modification

The Autoline 6077 is set up for a heat riser choke assist, you will just swap your old choke cap to the new carb.

You will also have to provide a filtered air source for the internal choke pull down.
You will run a hose from the port on the top of the carb See Pic #2 below to the heat riser feed See pic #3 below screw a hose barb into the port on the choke and hook up the hose and you are good to go and you choke will function as it does now.
You also have the option of capping the choke hot air feed off with a screen filter and just capping the port at the top of the carb.
Holley uses these screen filters on their carbs as they use the same basic system.
This would require getting the cap/filter ( I have not been able to find them separate might involve a call to holley) or make your own using a 1/8 " NPS compression nut and a small piece of fine mesh screen or copper/brass wool. Regardless you will need an NPT to NPS adapter to screw the filter cap to.

If you have any more questions just ask...

 

Okay great, thanks for the help. So I can swap this out, and aside from changing out the cap and running a hose from those ports in pics 2 and 3, I can get it running and worry about capping the choke hot air feed later?

 

Yup, not sure how you'd set it up on your new carb. Both rigs that I've owned the manual choke control was a stock item so no rigging up was needed. Both were cable actuated to the dash on the left side of the steering wheel. Starting was a breeze in cold weather with the choke on. Just pull out the **** all the way and then slowly push it back in. You had to continually back off on the choke **** as she warmed up in super cold conditions. Old school like me.

Many small engines today are still operated that way.

 

Running a hose from the ports in pic 2 and 3 will take care of the hot choke issue.
With the choke cap you have, you have you do not need the hot air for the choke.

If you choose to use the filter option on the port in pic 3 THEN you will cap off the fresh air feed in pic 2

 

You do not have a "mixture stepper motor" on your feedback carb.

Jim

 

Running a hose from ports 2 to port 3 will bypass the hot air choke. Only do this if you are going to change to a manual cable operated choke control.
The link I provided in post 2 has info (post 10 of the linked thread) on how the "hot air choke" works. I am not sure if you are taking the time to read these threads... you should, they have good info.

The carb you linked to in post 1... still needs a way to move the choke butterfly to the full open position. This is done with the "hot air choke" system.

Jim

 

I appreciate your responses, and I did go through and read those threads, though I may not have understood everything I read. I'm a beginner mechanic.