Choke help

which carb?

Unfortunately I don't have my Jeep yet, so I can explain in generic terms.

There are 4 things to look for in a properly operating choke.

1. When cold you obviously want the choke to close to aid cold starting and idling during warm-up. To check proper operation of this, basically you just depress the accelerator when the engine is cold enough for the spring to close the choke. This should happen anytime the temperature is under 65-70 degrees. The choke should not close all the way, but should have roughly

1/8" opening with the engine not running. If this is not correct, there is an adjustment for this. It sounds like yours is correct because it does start properly.

1. After you start the engine the choke should open slightly because there will be a diaphragm called a choke pull off that will be actuated by engine vacuum. This can be considered adjusted properly if the engine starts and then idles fine when cold. If the engine starts and then dies, the pull off linkage usually needs to be adjusted to not pull the choke open quite as far This is normally done by bending the linkage arm that runs from the choke pull off to the choke plate in the throttle bore. If the pull off doesn't do anything, then it is either faulty or it isn't receiving a vacuum signal from the engine.

2. The idle speed during warm-up may be too fast or slow, this is usually a screw adjustment on the passenger side of the carb. The screw will sit against a stepped cam connected to the choke linkage. I normally set this by having the engine completely warmed up and then moving the stepped cam so that the screw is sitting against the highest point. Your engine should idle about 1500RPM at this point. This is just a starting point and can depend on how cold it gets and even varies from engine to engine, but it is a good starting point.

1. The temperature that the choke opens up is adjusted by turning the black plastic housing on electric chokes, or by bending a linkage arm on the divorced style chokes. This sounds like it is probably what isn't right on your choke. If it is set too lean, then the choke will start to open before the engine is warmed up enough.

To properly set the choke up for your vehicle/climate I recommend doing the steps in order of #3, #1, #2, $4. The carb rebuilder usually sets these items up to a factory setting specified with the rebuild kit, but many times these need to be adjusted to get the vehicle to run properly. I rarely find them to be right, but it gets quite cold here in the winter. Normally I compensate a bit by adjusting the pull off to not pull quite as far, and possibly richen the choke spring adjustment (#4 above) by one notch on the spring housing. It doesn't take much of a change to make a big difference in how the engine runs cold, so do one thing at a time and make small adjustments.

Chris

To add a bit to the good info posted already, the choke is a timer type.

It opens according to how long it has seen 12 volts. It has no clue how warm the engine really is.

Most of them should have the black cap set 2 notches rich. You can go more, but it needs to be done when the engine is hot and running so you don't make the choke start to close by turning the cap too rich.

Even richer it will still go off to fast in my opinion. Especially in winter.

The fast idle is set with a fully warmed up engine. You put the fast idle cam adjuster screw on the second from top step and set the screw until you have 1750 rpm. This will give you 1500 or so cold.

As mentioned before, I got tired of 3 foot driving with an idle that had to be held at 1200 rpm or it would die until it 'really' warmed up so went manual. Choke half on works perfect for that. 1200 rpm right on. Just helped a gent go manual in his YJ before winter a couple weeks ago. It is pretty common up here in Canada.

Mike

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

Evan wrote:

guess Mine is working, I'll waite untill real winter to re-evaluate

83 CJ 8, a work in progress out the "XXX" to e-mail me