Truck will not idle maybe vacuum leak?

Hey everyone I bought a 88 Mazda b2200 a week ago it's got a 5 speed and had a webber carb on it, ran like complete shit, ran wayyyyy to rich and when I would try to lean it out it would just big down and die just was terrible so I took it off and went to my local wrecking yard and got a factory carb to put on, once I got it on it won't idle at all the only way I can get it to idol is if it's at 1500 RPM's once it gets below that it just starts cutting out running rough and dies, also drives fine no miss when I'm driving has decent power but when I come to a stop and put the clutch in it either immidieatly dies or idles at 1500 and then after about 1 minute sometimes will start cutting out and dies, I'm gettin frustrated can somebody please give me a tip or an idea of what's going on with it

Using a Weber carb and eliminating all vacuum leaks - sand the adapters flat, use Permatex Aviation (brown goo) on the gaskets - is a surer bet than the complicated stock carb. I've been running Weber on my B2200 for a decade.

I'll have to try that then I think that the carb has the wrong size jet in it tho, is it difficult to change out the jets on those?

Have you put a vacuum gauge on the engine ? Are you sure its a vacuum leak?

I haven't put a vacuum gauge on the truck yet. does anyone have a diagram of the vacuum system on these trucks?

See http://www.mazdatrucking.com/B2200/Vacuum.html

Ok so I got all the vaccum leaks
Worked out and now it will idle fine at 1k RPM's when it's cold but once it's warmed it won't stay idling at all won't even attempt to idle

Did you check your carburetor choke? Like when the engine is all warmed up, take off top of air cleaner and see if the choke butterfly is essentially vertical, completely open.

Yep it's opened up all the way, but if I partially over the carb with my hand then it will smooth out significantly and idle when it's warmed up,take my hand off and it starts to cut out and die

Your hand is limiting the amount of air getting in, so you're running lean once warmed up, and your hand there restores correct/close air/fuel ratio. Are you sure it's not sucking in air SOMEWHERE ????