purchased a 93 b2200 several months ago when i purchased it it idle'd high the man i bought it from said it sat up and just needed to be driven he had claimed to put new carb on it and the more ive driven it the rougher it runs at a idle and throwing lots of black smoke like its running rich how is there a way for me to check the carbs proper adjustment??? any help would greatly be appreciated and what else should i check??? ive tuned it up with plugs etc. already.runs smoother but still getting black smoke.

 

Carbureted you say!
Read: https://www.mazdaforum.com/forum/maz...version-30671/

 

Carbureted you say!
Read: https://www.mazdaforum.com/forum/maz...version-30671/

 

Aaaaaaah, the old days!

Do not use any ethanol blend. The rubber parts are not resistant to ethanol.

It's not enough to plop a new carb on the intake and you are done. That sucker must be properly adjusted. The float valve, the idle air screw, the idle speed screw and the choke need attention. There are a few other things but the things I mentioned must be right first.
Without specifications you have no chance. If Noggin's links don't give you specs you need to find them in a Chilton's or Haynes manual. Check your public library's non fiction section.

 

It's more than a carb change, it's re-doing all the vac lines which creates emission controls.

Quotes from article:

The bulk of the emission controls are mostly handled by vacuum switches and dashpots. To that end, they wound up with a HUGE mess of vacuum lines that plagued this truck's performance ever since it was first on the road.

Here is the "infamous" Mikuni Solex 2bl carburetor -- a design way past its time; even back in 1988.

Most of these lines are now solid and cracked from all the heat -- that causes lots of vacuum leaks down deep in these vacuum line manifolds. I don't have a vacuum hose diagram, so I just take pen and paper and label everything that's important.

all the brittle hoses and corroded clamps that had to be disconnected.


I can see why this thing ran so rich and smoked so much -- just look at all the raw fuel that's dumping down that intake. There's a "lake" of raw gas in that intake manifold.

Hooking up a vacuum pump to that secondary dashpot shows a little movement, but not enough to fully open the throttle plate under heavy acceleration. That's what was causing my power loss and hesitation when trying to accelerate at speed, and why the damn thing idled pretty well; the primary was working at idle, but the secondary wasn't opening under load. That's probably also why the raw gas wasn't atomized in the secondary and just filled up the manifold.

The benefit of that Weber kit is that it will eliminate 90% of all that vacuum hose garbage and will deliver a better breathing engine.

The vacuum line from the carburetor needs to go to the distributor. This is the vacuum source for the advance on your distributor. Without it your spark won't advance, and the engine will run poorly.

 

black smoke usually is raw fuel, rich condition. like the previous replies state, things have to be considered. first, all emission controls and vacuums have to be checked. second, mechanical; vacuum advance, ignition, spark plugs, coils and wiring. last, carb. quick, but not a bulletproof test: disconnect a vacuum line after the carb, and see if the amount of black smoke clears a little. if it does, you might need to adjust the carb. when you open a vacuum downstream of the carb, you are letting in more air than the carb is adjusted to creating a lean condition. if the black smoke clears a bit it means the air to fuel ratio got better. what brand is that carb? weber carbs are very popular in those cars and they are very easy to tune, just do a little search in google and you will probably fix your issues. also, is not only a matter to throw any carb into the car. it has to be properly sized to the engine. please, give us feedback on further developments. if you have a weber, you can start by checking this link: http://www.carburetion.com/Weber/adjust.htm