I have a Mcculloch eager beaver chainsaw. It didn't run when I got it so I installed a new carb. Seems like it has a priming problem. I'd spray starter fluid in carb. after about 10 pulls or so it would act like it is trying to start. I had it running for about a minute priming carb with starting fluid. Now I cannot get it to run. Still acts like it is trying to start when using starter fluid but will not run. I checked the spark and it seems to be good. I don't understand why it won't stay running when the carb is new. any advise would be appreciated.