i have a 85,with a 13b holly 650 double pump carb.ive been having problems with the fuel bowl adjustments in the secondaries.it seems as if i'm building presure.when i set the fuel bowls were they need to be,at first it runs ok.i'll take it for a drive,and when i get back it starts to over flow.i'll take the little screw out to check the level and gas starts to poor out.when it starts to do that,no matter how low i put the fuel bowls,it will keep doing that.it has done this with 3 different carbs.please help!

 

Check and make sure there isn't any trash getting in the needle seat. If fuel is getting in the floats, they wont float. Make sure ur fuel pressure isn't too high keeping the needle seat from closing off fuel supply.

 

ive checked that.there is no trash getting in.ive had this problem for about 8 months.i'm going to change the needle & seat again and see what happins,but like i said ive had this problem with 3 carbs.hopefuly it works.