Nutter modification and carburetor functioning

I made the Nutter Mod to my 1984 off-road CJ-5. The choke seems to stay closed too long and I get black exhaust and rough idle after starting. Once it warms it runs smoother although not perfect. Does the automatic choke continue to work after the Mod? I have not seen anyone address this issue. What can be done to improve these conditions? Thanks in advance. Les

Did you set the carb mix up manually via the two screws down front?

I have found that the idle and low speed set up ok following the directions, but top speed is 'way' too rich with lots of black smoke.

I have done more than a half dozen of them and I find setting the stepper pins in the center of their travel where they are 'supposed' to be before the O2 sensor input adjusted them is the way to go. This gives a clean high speed burn and over 20 mpg on the highway. I think this is two clicks or steps from 'pins in' or the full rich Nutter calls for. I can adjust them by rocking them with a mini screwdriver from the top.

I also have had 'all' of my 'Nutter' jobs pass Canadian tailpipe emissions with nice low numbers so my idea of having the pins in the middle also works for the emissions sniffer.

The choke is on a purely electrical timer circuit which isn't affected by the Nutter, only by how long power has been going to it. It might be a notch rich if you have the pins full rich. It can be adjusted on the side by turning the black cap after loosening those 3 screws. You will need a right angle screwdriver to loosen the screws or a screwdriver bit held at a 90 in visegrips.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: N>

On Tue, 14 Nov 2006 18:02:29 -0500 in rec.autos.makers.jeep+willys, Mike Romain wrote,

Now see, that's exactly what I thought, too. (And still do.) Then you told me I was wrong and they should be all the way closed.

snipped-for-privacy@sympatico.ca

I have sense convinced myself that I was wrong on that post and the 'Nutter' directions are wrong on that, sorry.

I started to do a test of the positions of the stepper pins about 3 years ago, then got banged up as a passenger in a car accident and totally forgot about my test and the reason for it. Meanwhile I had left the stepper pins all the way in by hand, not by computer. In the past I believe I have had the engine running warmed up and think I got the pins centered by default due to totally dead emissions and the 'limp home mode' factor. Because this worked so well and passed emissions, I forgot about using the nutter directions to full rich it or because things were dead, the 'full rich' directions didn't affect the stepper stuck in it's limp home mode. Dead O2's maybe, not sure.

I then, with the pins all the way in, got terrible mileage, especially on that long trip last summer. (first time I paid attention to mileage again) I attributed it to all the gear on the roof rack and back rack along with 3 adults inside. I was wrong. When checked empty I was still getting crap for mileage and my top end was down to 4000 rpm max.

I was sitting thinking about the crappy mileage and reading about others doing the 'Nutter' and suddenly remembered the 'test' I had started. It might have even been that thread you quoted that got me thinking.

So I went out and used a mini screwdriver to push by rocking them, my pins back into the stepper a couple steps so the pins are in the middle, reset the idle mix screws (off only 1/4 turn) and on the next trip got my mileage back up over 20 mpg with the top end back to 4400 rpm. I am still pissed about the mileage on that trip last summer. Grrr....

I would recommend you play with those pins and see if centering them improves things.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 (More Off Road album links at bottom of the view page)