Non efi 700 dies when going uphill

I’m thinking I need to rebuild my carb but wondering if it could be the fuel pump or both. I use this almost everyday to check cows and noticed it a few days ago when I popped a wheelie. At first I thought I imagined it sputtering after I brought the front end down so I popped another and held it up longer. This time it almost died but after a few seconds it ran as strong as ever. Tonight I had to winch myself out of the creek with steep banks to get it level so I could start it again. I rebuilt this carb awhile back and put a dynojet in it and never had a problem till recently. Am I right on my thinking that it’s possibly a stuck float. I’m not sure how the fuel pump works on these non efi’s and never had one apart but wonder if that could be an issue with it not being level as well.