First time carb rebuild
 

So I still tug my boat around with my 1978 F150. It's not ideal in terms of space and power but it more than gets the job done and I can't bring myself to get rid of it. It's been running pretty rich and spitting some black deposits for about the last year so I decided to get a rebuild kit for the carb(wiring is in great shape and I did the plugs last year). Can anyone give me some definite do's and dont's or some general insight regarding the job? The truck has a 351m and still has the stock 2 barrel motorcraft carb.

i would just buy a new carb from summit
$100

Any thought of an upgrade to a Holley or Edlebrock? I just completed my first carb rebuild on a Holley 4160 for the 351 in my boat, it was fairly straight forward using a workalong book for instructions.

Get you a good HOW TO book and read it before you start. Take plenty of pictures from all angles as you go. Take your time. Clean everything very well. You will need a gallon of carb cleaner with a dip basket (not the aerosol cans) and compressed air along with a few small opne end wrenches and screwdrivers.

Do not take the butterflies apart unless they are broken, just clean them good.

In all, if you can get a new one for $100 you would prob come out ahead. Rebuild kit is $35 I think, $30 for a HOW TO book, $20 for gallon of chem clean, plus whatever needles, diaphragms, etc you might need that dont come in the kit.

The cheapest price I've found for a rebuild is right around 200.00 plus core. I already bought a kit along with a new float for 25.00. Didn't realize I'd need that much carb cleaner though so thanks for the heads up. The kit seemed to have pretty detailed diagrams in it and I'll definitely take a bunch of pics. If somebody knows of something for around 100.00 post the link - I'd be all for that.

Keith,

That is probably the same carb I have in my Bronco (Motocraft 2150) and it is an easy rebuild. You can go with a new/rebuilt Holley 2300 series or an Edelbrock and not see much gain in terms of performance (at least that's what I found with my rig). Depending on the carb, you may also have to get an adaptor for your maniford and reengineer you accelerator linkage. Rebuild is the best bet IMO.

Tips:

Get your baseline for all mixture screws by slowly turning them in (counting the turns). This will help you in final assembly/adjustment. If you carb is like mine, there are two idle mixture screws (one for each barrel) at the front of the carb on the flange.

Take pics of all linkage assemblies before you take it apart- the diagram that comes with the kit is great but is often for multiple carb setups (Ford used this same basic carb for a number of years).

Replace the float assembly. This sometimes comes with the kit...sometimes not.

I agree with Chris- dip the carb. Blow out all areas with compressed air. Make sure and set your float level (in the instructions). At the same time, replace all fuel filters etc. Fire her up and make your final adjustments on the idle mixture screws, linkage etc. You should be good to go.

Paul is right on. If you don't have access to compressed air, then consider getting a source (buy or borrow a compressor). I've cured a lot of problems by cleaning carb passages with compressed air. Blow out any passage you can. Remove all the mixture screws, jets, etc and blow out all the passages.

Also, check for play at the throttle and choke butter fly shafts. Excessive play and you'll never get your adjustments to hold (idle, and fuel mixture). A bit of play is normal, but if you've got an 1/8" of play (up/down) then you could have a problem.

Definitely replace the float, and set the level per the manual. The new float will not be set at the correct level.

If the idle still kicks in most of the time should I still go ahead and replace the choke? I didn't get the part yet but the local shop has it in stock for 12.00. I do have a compressor so I'll drag it out and give it a good goin over. Thanks for the tips.

Electric, heat, or manual. Ford used it all. I'll assume you have an electric choke, and I don't see a need to replace unless the internals are broken (you can pull the cover off to look). The choke only moves the top butterflies and isn't part of the fuel circuit. It can get out of adjustment and cause your truck to run rich although. When truck is warmed up and engine is running, butterflies should be wide open. If not, choke is stuck. Usually can be adjusted by rotating the choke assembly.

Use empty egg cartons to organize the parts as you take it apart.

I'm also gonna say that the choke might actually be your only problem since it's running rich. Replace that first IMO. Clogged carbs normally cause a lean condition, not rich.

So I finally set aside the time to get this done and everything seemed to go reasonably well. I do have at least one problem though. At regular idle it seems to be starved for fuel and wants to die unless I rev it up a little(same thing when i slow to stop). Does the choke just need to be adjusted or would it be something else? I also forgot to pay attention to the high alt/standard alt setting when I took it apart. If I'm just under 5000 what setting should I be on?

There should be an idle mixture screw on the side of the primary metering plate. If its dying at idle turn the mixture screw out until the idle smoothes out.