G1, idles great, runs rough, runs better when warm

[Halw2006]

Im new to posting but have spent several days reading the forum for advice. Thanks to all who have posted about g1s. I just bought the cart and was told its an 81 Yamaha g1. It's stock. I use it to drive around a large property daily several miles. The problem is the cart seems to cut out under power. If I choke it. It will power right back up. So it's choke on, choke off, repeat. It idles great. Starts instantly and runs rather quick. I've cleaned e carb, and sprayed starter fluid around the seals. The motor didn't sapped up with the starter fluid so I presume the seals are okay. The plug is brown so mix seems ok. Any ideas? Thanks in advance for any help