Hey i have a 1981 fb and it will run start and drive but it doesn't want to idle any suggestions of what to fix about why it wont idle????????

 

welcome to the board.

here is a link to get a copy of the FSM: Foxed.ca

my first thought is that you probably have a vacuum leak. you need to find it and fix it.

 

Fuel and air in the correct proportions are necessary. Vacuum leaks upset the ratio and volume you planned by way of the two screws on the carb. Split old hoses, overlooked connections and intake manifold leaks are prime suspects.
The FSM mentioned in an earlier response is vital and free.

 

Vacuum leak or fuel problem. That's a simple translation of what the other guys said. The stock Mazda rotary has a lot of vacuum lines and solenoids (the rat's nest). When it's all in good shape the engine runs great, but after 30+ years those rubber and plastic bits dry out and crack.

Go over all the vacuum lines and look for cracks and leaks. You'll learn a lot about your engine and the parts are cheap (vac hose and rubber nipple caps).

Look for fuel problems... dirt in the fuel, clogged filter, etc.

Make sure the plug wires are arranged properly. Easy to mix them up.

Rotaries are unusual engines and most mechanics are unfamiliar with them.. But really they are very basic and follow the same basic rules.... fuel/air/spark.

 

My first question when this topic comes up is, when was the carb properly rebuilt last? Can you see sediment in the fuel filter? All too common sediment plugs up the filter and the carb. Causes all outs of idling and driveability issues.