1990 b2200 - idles too low cold and too high warm

Hello to all--new to the forum and just got a carbureted 1990 B2200-- Need some help please.

It had been thoroughly ignored and abused by the previous owner-- needed all the normal stuff under the hood.

I replaced all the bad vacum lines I could find plus, cap, rotor, plugs, wires, 02 sensor, air filter, pcv valve and gave it a general cleanup. Also removed "exhaust" lines from air cleaner and plugged them off, knocked out the plugged up cat, installed a new muffler,pulled and cleaned the egr, cleaned the choke linkage and confirmed that the choke is closed cold and open hot. Fuel filter is also new--no sign of crap in the old one.

I leaned the idle mixture till the rpm dropped and backed it out about 1/2 a turn. I've fiddled with the mixture screw some and it seems happiest about there. I checked the mixture solenoid with a dwell meter using the test plug on the fenderwell and get a constant reading at idle but at the moment cant remeber what it was.

All that dramatically improved the way she runs and also nearly doubled the mpg. Runs a lot smoother and stronger too but......I can't get the idle right. When warmed up I adjusted the idle to about 750 or so and it seems about right. Upon cold start up it will only idle at around 450 give or take--once warm its back up to 750. If I adjust the idle while cold to 750 when warmed up it idles up around 1100 or so.

There apears to be some linkage missing on the carb but being a Mazda newbie I'm not sure what should be there.

Also get a slight hesitation off idle and when transitioning from coast to throttle.

So all you Mazda Pros---what gives?

Thanks for your help----

when cold starting, it will always idle lower until it warms up, mine will barely idle without the choke when I first start it, then when its warmed up, it idles between 900 and 1000. so u kinda just gota compensate the idle screw, theres a high idle screw for when the choke is on that u can adjust for high idle, then theres that screw that sticks way out, and that's the reg. idle screw, (assuming u have a stock carb.) as for the hesitation, the main reasons ive ever had hesitation was either a lean fuel/air ratio due to a vacuum leak or my timing was off. I tell this to a lot of people, when u have an issue an think it may be a vacuum leak, spray some starter fluid around carb and intake, if theres a leak, the fluid will get sucked in there and u will hear the rpms change and if there is a leak, youll find it.

Are you talking about what looks like an extra cam wheel on the throttle for an additional cable to be attached? If so, that would be for optional cruise control cable attachment.

I have almost the same problem with mine but it's webbered it'll idle at like 400-500 when cold and then moves up to about 800 when warm if I adjust it up when cold then it idles at 1300+. Also when cold the motor stumbles on accel till warm. I've checked for vacuum leaks and I adjusted the carb (it's better not it was real bad before...) but it still happens For the first 5-10 min after cold starts. Thanks guys (sorry for the thread jack) and I'm sorry I'm not much help....

Fred

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Hmm must be a weber thing mine does the same stuff.

My B2200 with Weber doesn't do that, runs smooth from idle on up. Whether AC is on or not.

Mine runs smooth too just not when cold. I mean if I let it warm up for like 5-10 min it does fine but sometimes u gotta go now and don't have time to wait and it usually dies once if I try and take off before warm. Idk I'm not complaining too much though it's much better than the stock carb, my stock carb did the same thing only worse and it took almost 30 min for it to run right in the cold. Wait Cusser do u even have cold starts in your neck o the woods?

Fred

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Wow, you guys totally jacked this guy's thread.
I wonder if he'll be back...

My bad man I ain't trying to. I didn't think it was necessary to create a new thread about the same issue (kinda)

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