carb running rich

[strvger]

ok, really black inside my tail pipe. mileages sucks. i think my carb is running rich. does it have to be removed and somewhat taken apart to get to the air/fuel adjusting screw (s)? all i've found on the outside are the idle adjustments screws. what am i missing?
thanks in advance.

 

[Big Jim M]

Is it smoking black smoke with perhaps even some flecks of soot in the air behind the tail pipe?
Does it idle well? Black inside the tail pipe doesn't mean much anymore. Carbed engines run a little richer than fuelies do...that's why we went to fuelies in the first place.
Big Jim

 

[schmoo]

air fuel adjusting screws are put on by
experimenters (like me)- they aren't stock.
i would suspect the computer, the solenoid
on the back, or the power valve.

 

[strvger]

idles a little rough, but not bad. it could be smoking black, but the valve seals are pretty bad so most of the smoke is blue. i really was expecting more than about 17mpg out of it. heck my old Suburban V8 auto got almost as good (16mpg) as this 2.8 with a 5 speed!

 

[Big Jim M]

If you are getting 17 mpg out of it..you are good! Leave the carb alone, it isn't doing anything bad.
Big Jim

 

[strvger]

ok, well maybe i'll think about tinkering with new gears to at least get a little more power for my mpg's. original tires were 205/75x15 with the 3.45's. now running 235/75x15's and have some 31" tires available. maybe 4.56 gears would help me keep my foot off the throttle a little.

 

[dangerranger83]

17mpg....your lucky. My dads is getting 14mpg now.

 

[BeaterMan]

yea 17mpg is awsome. I think I may have topped out at 12mpg ONCE. but then again i do have 33's and 4.88's - i'd leave it if your getting that mpg's

 

[Eric Kropp]

I would check the idle/air adjustment screws. If they are more than 1-1/2 turns out you are going to run a little rich. Also, check the float level adjustment. 17mpg for one of these is about average. Mine gets 17 to 19 with a little combination of city and highway, mostly highway. If I take it just highway at 65mph it will usually do a 20-23. I would yank the carb, get a kit and give it the dunk in some gunk over night then reassemble very carefully after blowing out all the passages or using brake clean to clean them out. I would check the timing to.

Eric

 

[tnt4me]

I agree with Eric. I just rebuilt the carb and now it runs great. The screws you are looking for are in the front bottom of the carb. They may have "locks" over them which make them look like two black knobs. Those are a pain to get off, but once you do, you can adjust them. The guide I followed worked real well. Turn them in until you feel them snug up (do not over tighten as this will ruin them). then unscrew one and a half turns. Continue unscrewing until the truck starts and idles by itself. Then one at a time, adjust each screw (count 1/2 turns) until the RPM's go up, then back to original, then the other way till the RPM's sink. Adjust back to best Rpm you heard.

BTW, the rebuild kit was $30 at Checker. NAPA wanted $80. It is an easy job to rebuild, take your time. I found good instructions on the web, just type carburetor Model & # rebuild (Motorcraft 2150) .Also by a new float as they wear out after about 5 years or so.

 

[strvger]

thanks for the info! think i might try the rebuild and just leave those "locks" off so i can adjust it as needed. my driving is mostly at less than 1,000 ft. above sea level, but summer trips see my truck at 6,000-10,000 ft. would be nice to be able to lean it out a bit at the higher elevations. i appreciate all the help!