new motor will not idle

bought a long block off of CME,great guys to work with,but as luck would have it (bad) sent the wrong rotation engine ,found that out a little to late had everything put together ready to install all the way up to the distributor didn't slide into place so tore it all down and sent it back. got the right rotation one back installed it took her down to the river and by the way i did rebuild the carb, boat was sitting for 4 years and the carb was pretty bad . couldn't get it to idle below 1500r's timing was on.and as i tried to get it lower it would just die off. plus it was hard start again. It seems to be sucking to much air from somewhere . and i did put all new gaskets on . any ideas thanks

thank chris i will do that and let you all know what i find

Hi Paul It was the 81. I did try to mess with the idle mixture screws holley web sight said to start with 1 1/2 some told me a 1/4 turn out by then the carb backfired so i figured out i was done probably blew out the power valve bought a new one give it another shot some time this week. Got a pig roast this weekend down at the docks , come on down if your free bring nan and peanut

pig roast is on saturday but shell and i will be down all weekend . Sunday will be great we will save you and nan a dock slip let me know call 412-965-0166