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Balsax
10-20-2003, 03:04 AM
Hello-
My friend just bought a '76 cherokee chief. After starting it up, we noticed it was running VERY rich. It is blowing a little black smoke and once in awhile, it will puke out a a big black cloud. It is leaving black residue where the exhaust is blowing onto the ground (not oil). I live at 10,000 feet so carbs have to be adjusted for altitude. I think that the jets are already smaller than stock so I think there is another problem. The choke is opening like it should, the main jets are 46's, and the timing is where it should be (around 8 bdc). I think the needle and float are working ok. Anyone have any thoughts or does anyone know what the factory jet size for this carb is? By the way, the carb is a 2 bbl motorcraft.

tgreese
10-20-2003, 03:23 AM
Just as a ballpark figure, I scrounged a couple of 2100 Motorcraft 2Vs recently.

'79 360 2V Cherokee, EGR, 2-stage power valve: 44
'79 (?) 302 E-100 Ford, 1 stage power valve: 46

You might try replacing the power valve (aka economzer valve). Smaller jets are availble from Parker Carburation.

Balsax
10-20-2003, 03:29 AM
Is there any way to check for a bad power valve?

Balsax
10-20-2003, 06:56 AM
I think I found the problem...
I took the carb off and turned it upsidedown to empty it. Nothing came out. It hasn't run for about two days so the fuel must have gone somewhere. I took the top off the carb and verified no fuel. I then took the power valve cover off the bottom and noticed it was full of gas. Gas shouldn't be there. I took the power valve out, dried it, and did a high tech vacuum test (put my lips on it and sucked!). Air was going past the valve. This would explain the very rich mixture I was getting. I like when these things turn out to be quick fixes!
Thanks for the sugestion, tgreese!

Mike

letank
10-20-2003, 09:05 AM
Also make sure the power valve is connected to the intake manifold vaccum....

Cheers

MIchel