i have an 87 brat that once i turn the ignition off it sputters and cutts up for about 15 seconds afterwards

 

 

 

since im a rookie i have no idea how to fix this im sure its just some minor adj needed but i have no idea what to do or where to start

Check ignition timing...should be 8 deg BTC. Also make sure all the mounting bolts on the carby are tight. Finally, could be a faulty anti-dieseling selonoid but I've only read about that and have no clue how to troubleshoot. I've gone to the Weber carb so I don't have one of those any more.

 

Yup, this is called diesling - could be a number of things, check that ignition timing is set correctly and that idle speed is correct. If this doesnt stop it could be the anti-diesling solenoid on the carby, get one from JY and see if that changes it. Mostly I find this has occured due to timing.