Just screwing up my carb settings...

[Cool Wheels]

I'm going to ask this at the risk of sounding stupid. Is it possible to increase the richness of the fuel mixture related to the choke setting on a cold engine? The choke has a black dial that says rich > lean <. It has adjustment screws. Does my answer lie therein? Will the mixture lean out after the engine warms up?

My Haynes reference manual has absolutely nothing on this for the 2150 2V.

Here's my problem: The mixture seems a bit lean while the engine is cold. It stumbles and bogs out while cold. Purrs like a kitten after the choke opens up. I've looked over the ignition system. I know some of you will tell me to take out the auto choke but I'd rather try an adjustment since the carb is fairly new (the old one had parts missing).

Ok, I know sometimes my questions are pretty simpleton. I'm learning as I go and am a hobbiest with no mechanical work experience. To be honest I'm learning as much as I can by reading but what can you do when the stupid reference manual doesn't tell you anything?! I hope that if I ask enough stupid questions, I'll eventually be smart - works for some people!

 

[COBRAIIW]

When cold,the choke should be set at about 1/8" open.
you loosen the retaining screws and turn the choke (black cover) until you obtain this setting.
the choke should not be fully closed,or too far open when cold.

 

[Blue Thunder]

Experimentation with the choke setting will not harm the motor. (Assuming you don't leave it running extremely rich, which will wash the oil from the piston rings and cause premature cylinder/ring wear over time.) Are you certain it's too lean when cold? If the choke is set too rich, the motor will stumble, although usually when it's that fat there's some black(blue/black) smoke, too.. Is the fast idle working properly? The fast idle RPM is adjustable.

 

[Cool Wheels]

Thanks for the info. I'm going to try the choke adjustment tonight.

I've tinkered with my fast idle. Problem I've had is that there seems to be several different stages of "cold" and if the fast idle is set to run around 1000 rpm at the coldest engine state then it usually ends up around 1300-1400 rpm when it's fully heated prior to kicking it down, and that just seems and sounds way too fast! Right now I have set to about 1000 rpm at hotest stage prior to kickdown, which means that's it's at 800 or so when it's stone cold. After the choke opens up it runs at a steady 500 in gear, 800 in park.

I do have a small vacuum leak through my power brake booster but I don't see why that would only cause the problem when the engine is cold. My vacuum test resulted in a healthy "18".

I'm also going to do a compression test this weekend. I've been putting it off for too long! If I can't figure it out I'll give in and have a pro tinker with it before I go nuts! Thanks again for your insight. Sometimes I'm just not 100% confident about messing with something. I'll repost if I have any breakthru's...

 

[THE COBRAMAN]

Spec on the high step of the fast idle cam is 2000 RPM.

Are you sure the choke is getting power? My '77 gave me fits last winter, as it would start fine, but die once moving. It would eventually get warm enough to not be a problem, but what I found was that the hot wire to the choke from the back of the alternator was making intermittent contact with the stud. The terminal is just a simple ring molded into the connector that friction fits over the stud, and over time had loosened to the point it wouldn't supply power once air coming thru the radiator and from the fan "wiggled' the wire a little.

Like was said previously, adjust the choke plate to have very little gap when stone cold, and you should be able to adjust the fast idle from there. Once the engine runs at 2000 a minute or two, you should have made enough heat to get it to kick down to a more reasonable level. Having the heat riser pipe from the exhaust manifold to the choke will help with warmup time as well, but most IIs have had them removed eons ago.

 

[Blue Thunder]

If I recall, a stock(or mostly stock) 302W engine makes 21" vacuum at idle. Vacuum leaks can really lean out the mix at idle, especially noticable when the motor's cold.

 

[Xanax]

I agree