I have an old Stihl fs 80 trimmer. Always ran good until the spark plug wire broke. I bought a new coil. Just a cheap one from Amazon. Since I was getting the coil I went ahead and got a new carb and air filter and spark plug. Also cleaned the spark arrestor. It has good compression, new coil, spark plug, carburetor, fuel filter, fresh new gas. You can prime it, choke it and it starts and dies. It will start and die . Fuel lines are good. Also switched gas caps. Still nothing. Any advice will be greatly appreciated.

The carb most likely needs adjusting.   
 
The 2 screws, next to each other, are the low and high speed adjusters.  
 
Opening, richening the mixture requires the screws to be turned counter clockwise. The screw closest to the engine is the low speed, the other the high speed.  
 
To set the HS, open up (probably) the screw 1/2 turn plus to get the highest RPMs. 
 
To set the LS, adjust that screw to get a good solid idle and the engine will start hot with no throttle input..
 
 
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New carb from Amazon or oem?