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AMC 150 too rich

I have a question concerning an '84 CJ with the AMC 150 4 cyl engine and one of those terrible Carter carburetors with a Nutter bypass performed. Keep in mind with this question that the catalytic converter needs to be replaced and another one is on order. Here's the present trouble: The stepper motor, which I believe controls the amount of fuel, has been disconnected as part of the bypass. The gas to air ratio is too rich and there is really no way to adjust it, or so I'm told. I'm not sure how much the catalytic converter has to do with this but, how can the fuel mixture be adjusted with the bypass in place?

Thanks,

Chip

Reply to
Chip
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did u make sure the stepper motor was in the right position before turning it off? i never did the nutter bypass in mine before i took it off but i remember you had to have the motor in a certain position before cutting the wire. is your 02 sensor alive?

Reply to
serg

The computer was not functioning so the stepper motor was inoperable (or at least was not being run by the bad computer) Before the bypass was complete, my father started the motor, it ran terrible until he uplugged the stepper motor, then it ran smooth. How can you tell where the stepper motor should be and how do you get it there if it is in the wrong place, which it obviously is because of the amount of gas running through it.

Short of solving this carb trouble, what kind of pre-83 carb will fit the

150 engine?

Thanks again,

Chip

Reply to
Chip

The stepper motor controls the air bypass only on the Carter BBD carb. This means full rich is pins all the way in.

I highly doubt you have a Carter BBD on a 4 banger though....

You should check to see what it is. They all are manually tuneable with 'hidden' mix screrws the same as the non electronic ones, but it is hard to point you the right direction not being sure of the carb...

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Chip wrote:

Reply to
Mike Romain

Ok, you have the YFA carb.

The fact that it runs pretty decent with the stepper unplugged would lead me to believe the mix is at least 'close' by default.

The YFA with the stepper still has the manual mix screw, same as the BBD. They hide it under a metal plug in the base plate of the carb. Some you can pull the blocking plug out with a point, others have to be drilled and pried out.

If you set the carb with the throttle lever in front of you, the mix screw will be in the base to your right under the plug likely.

I would highly recommend you get the Haynes CJ manual. It has a great section on the carbs.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Chip wrote:

Reply to
Mike Romain

Reply to
serg

Dad took the motor off and put a plate over the port in place of the gasket. We now suspect that it's not the source of the problem. The engine is just getting too much fuel. It will run but, it floods easily, and when ever it warms up, the fuel smell is very strong. To start it when it's warm, you almost have to treat it like a flooded engine just to get it going.

I told dad the there are a vast number of people on the newsgroups and someone will be able to diagnose the problem with us. Thanks to Mike, Bill and Serg for their help so far.

I believe that he is going to get a rebuild kit for the carb and go from there, but I will tell him about the mix screw location.

Thanks Again,

Chip

Reply to
Chip

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