Well I tuned up my truck after the first emissions failure. I even put in the junk in the gas tank, hoping it would pass the second time (today).

Well the HC readout was better but still 2X the limit (1148, should be 600).

So after the 30 day temp tag ($10) , and than todays temp permit ($10) and the $89 diagnostic at my mechanics they tell me the carb needs to be rebuilt.

They said nothing else showed up on the diagnostics. They think the float might be collapsed etc since it is blowing high HC (unburned fuel).

Do they experts here agree? I can't afford the $300 to pay my mechanic so I guess I will be doing my first carb rebuild.

MaxTek

 

is it just an idle test?
try leaning out the idle mix alittle and reducing the timing a few.

If you rebuild the carb use the carb cleaner thats in the gallon can from Napa.
use common sense with this stuff, it will eat a latex glove in about a min. (guess how i know)
The stuff in the spray can is like water.

 

If your vechical has a catalytic converter then it HAS to be hot before you do your test if not it will not work and will let unburned fuel vapors out. With your readings I think you have a mixture problem as you stated but just wanted to make sure.

 

Sounds a little rich.
Changing the oil is usually a good start.
I always dump in a about a half gallon of IPA (best % you can find) with a fill up of high octane.

 

The car was definitely hot before I ran the test.

After the first failed emissions I changed the oil, pcv valve, spark plugs, filters and filled the tank up with gas and that "pass emissions in a bottle" stuff.

What is IPA?

Thanks for the replies...don't stop now, I really need to get this truck back on the road legally.

MaxTek

 

IPA = Isopropyl alcohol?

 

That's it. But yout high HC's are 2X- It may need some leaning out as well. I assume you've got the timing dialed in as well.

 

Better get your money back on the pass-in-a-can.

 

I agree with the mechanic, time to rebuild the carb. I've got to do one myself. Hope it goes better than the PS pump I just did. That broke parts off the rotor and siezed up. Oooops. I don't think carb rebuilds are that bad. Just get a good book on it. Read the steps several times. Work in a CLEAN area. Spray the parts down well with carb cleaner and reassemble (use eye protection when cleaning). You could use brake cleaner as well. Leaves less residue.

 

You did not state your year or engine size. Just a curiosity really. The Autolite 2V carburetors that came on Fords for years were notorious for popping the diaphragm in the Economizer valve, read power valve. This usually makes one run richer than what you are stating. It could be too that the Economizer has become loose and has backed off.

At any rate, definitely kit the carburetor. I rebuilt the one on my 79 302 again a while back and discovered that the Borg-Warner kits have an upgraded power valve in them that's not near as susceptable to diaphragm rupture.

Remember too that idle is the richest running condition that an engine with a carburetor will see, and most fuel injection equipped as well.

The one main adjustment in the carb is the float. Make sure this is right, it aint hard, then check all your other listed adjustments as well. Probably the next most important is the accelerator pump adjustment.

With the new kit installed and a new fuel filter, start with the idle misture screws 2 1/2 turns out from the seated position. DO NOT force these scres in the seat. Just run them lightly till they stop and count your 2 1/2 out.

Let the truck thoroughly warm up.

At idle, make sure the choke is all the way open. If it isn't, stop and fix it. Is the choke pull-off good,will hold a vacum, and properly adjusted? The choke flap in anything but the wide open position will make the engine run rich.

At specified idle speed, pull the distributor vacum line(s) off and check the initial timing. A couple of degrees probably wont matter, but make sure it's at least advanced as much as the spec says. Timing advance, to a degree, (pun intended) gives you quicker power and more of it and better mileage.

With the choke right and the timing right and assuming that you don't have vacum leaks or major engine problems, you are now ready to adjust the carburetor.

Without a longer than already dialog, adjust the mixture screws one at a time for the most engine RPM and smoothest idle. If your mixture is majorly out you will have to bring the idle back down with the idle set and adjust the mixture again. Try to stay within +200 RPM of your specified idle when doing this. You may have to do this several times. A tachometer will help you do this. Just look for the steadiest, highest RPM. Make your final mixture adjustment at specified idle speed.

This is basic, but should get you there if you don't have other problems.

Bird

 

Wow, now I understand why they are charging 3 bills to rebuild my carb and adjust it.

At first I had doubts I could rebuild the carb but now I have doubts I can get the adjustments correct, but I have no choice. I have a timing light but no tach. Guess that will be purchased with the carb kit.

Texasbird and others I very much appreciate the time you have given me with this problem.

I plan on starting Monday moring.

MaxTek

 

Well, at least the tach and kit will cost you less than $100. Don't spend a lot on the tach. A cheap one will do. Mark all of your vacum lines and/or make a diagram of where they go. If the kit doesn't come with a base gasket, carb to intake manifold, get one of those too. Reply to this message or private message me and I'll try to help you if you need it.

You're doing the right thin in doing it yourself. If you're going to have an old Ford truck with the factory carburetor you have to know how to rebuild it.

Bird

 

Well here it is a week later and all I have done is get rebuilt carb pricing and remove the carb from the truck. Talk about procrastination! Today (Memorial Day) after finding out a kit is $26.20 minus the float. A rebuild is $130 I stopped over my cousins house. He said buy the kit and come over Tuesday night and we will do it together. He is the complete motorhead of the family, BUT a diehard Chevy man.

So I guess my question is should I go ahead and buy the float when I pick up the kit? The carb I am rebuilding is a Motorcraft 2150 2-V 1.2 from a 302 5.0L.

Thanks,

MaxTek

 

They are extremely easy to rebuild. All you really have to do is replace the power valve (one the front of the carb) and the accelerator pump (on the bottom of the carb).

The idle set screws will need to be adjusted and your timing will need to be checked, but thats about it.

 

Matts72 speaks the truth. Why can't I ever write a note that short that says what I want it to say?

Bird