1979 f150 Supercab 351m. I'm putting my c6 problems aside for now until I can afford a new torque converter and rebuild kit next month. Next issue my 2150 carburetor <br /><br />I bought this truck about 6 months ago from neighbor of original owner. Documented 70,000 original miles 72k now. I did drive it home but it was rough, parked it and made a plan. First on the list was to rebuild original 2150 carb. This is a particular job I had never done but I got the kit from Mikes Carburetor, took lots of pictures so I would make no mistaked getting it all back together right and vacuum lines in the right port. I took my time through each step and the rebuild went very well I thought. One thing I noticed is that the air metering rod assembly that would install into the venturi was missing completely and PO had put a machine screw in to fill the hole. I put it back like that. I did look for this part everywhere but could not find it anywhere online. Ok so other than that carb went back in fine and I adjusted everything back like it was, idol mixture screws etc. Truck ran fine but has never been perfect, I have always suspected a vacuum leak but was never able to locate. It always loped a little at idol but now that problem is much worse and I found yesterday that with truck up to temp on a hot day it runs better and loping almost disappears if I manually shut the choke. My experience in the past was if you did this the engine would die. Does this mean a MAJOR vacuum leak? What does this air metering rod assembly do and how bad is it that this part is missing? Appreciate any input. On another subject, any recommendations for a c6 rebuild also appreciated including recommended kit, torque converter and shoul

 

If you don't have a vacuum gauge, get one.

Hook up the vacuum gauge to a manifold vacuum source and, with the transmission in Park, adjust the idle mixture screws for maximum vacuum. You're looking for 17-18"

There should be two idle mixture screws. Start at 1-1/2 turns out, and adjust them both the same

If you have a tachometer, try to keep the idle speed in Park to about 800. You may need to adjust the idle speed.

If you have a timing light, check the timing

Do all this on a warm engine. Make sure the choke is fully open

After all the above is done, set the Drive idle speed to about 650, or as stated on the emission tag

 

I plan to pick up s vacuum gauge this week. Its been on my list of many tools that I need. Will try all that and report back. Thanks

 

Yesterday I picked up a vacuum gauge and started working on tuning carb. I hooked up gauge to manifold vacuum and it was low and needle was jumping all over the place. Obviously there was a significant vacuum leak which I pretty well knew with the engine loping like it was. I sprayed some carb cleaner all around base of carburetor and watching the gauge I saw it jump after I sprayed the passenger side of erg spacer where it sits on manifold. Seeing the gauge was very hellpful because hearing the engine speed up was subtle. Now my bright idea........I decided to tighten the carb bolts a little, I set my torque wrench to 15 lbs and went around and snugged them all up. When I got to the passenger side back corner closest to firewall, before The torque wrench clicked, I heard a POP. Ignoring this bad noise at first, I layed off the wrench, started truck and engine was terrible and vacuum leak was much worse and I could hear the hissing. I had cracked the back foot of carburetor right through where little metal tube is that goes to choke pull off. DAMM!
So after a slight meltdown and a lot of bad words I started taking all the lines and springs off and backing out the bolts to remove carb. All I had was JB Weld so thats what I used to "glue" the foot back on. I used a heater and a old tshirt "tent" to speed up curing process. I had about 3 hours before I had to pick up my wife at work. I was not optomistic. While foot was curing I found a new gasket to put under the egr spacer and after an hour and a half I put the carb back on, tightened the three bolts on no broken corners and hand tightened the bolt on corner with repair. I reset the idol mixture screws to 1 1/2 turns and started engine. So far so good. I hooked the vacuum gauge up and fine tuned until needle was steady at 18.
What a difference. Truck runs much better now at idol and at speed. I still have transmission issue of course but Im going to tackle that in a few days.

Anyone else have a carb foot snap off like that? Do you think the JB Weld will hold? Should I leave that bolt at hand tight? Vacuum leak is gone shockingly so I guess I had better leave it alone.

Btw, still would be great to have some advice on c6 rebuild. Torque converter and rebuild kit to buy and should i put on a shift kit? Thanks

 

Good save on the carburetor. I've heard of other guys breaking off the mount, and also fixing them with JB Weld. If it don't leak, I wouldn't mess with trying to tighten it any more.

No experience on the C6 rebuild, although I think it's probably not all that hard. Get the rebuild kit and watch the video until you know it better than the producer...

 

I checked for vacuum leaks again around base of carb again and there is a slight leak in same place under spacer where I repaired the foot. Ithink I will carefully and lightly snug up that bolt, I have yet to put a wrench on it. Other than that the engine is running great now. Getting the vacuum right was huge. The idol mixture screws ended up 2 1/4 turns out (they were at 1 1/2). I may be crazy but I notice an improvement in power brakes and tranmission too. Trans is still pretty bad though, I ordered a kit and torque converter this morning and reserved a rental car for a week so Im not stressed and I can take my sweet time. I looked at trailer for bad shoe video and Im definitely going to get that too. Was impressed at detail he goes to, thats just what I need. Thanks

 

The brakes and shifting both need vacuum, so fixing a big leak will make a great difference.

Sounds like you've got a good plan - best of luck on the transmission rebuild!

 

Something I found that might help? https://www.ford-trucks.com/forums/1...l#post14696849