1995 Kawasaki SS rough idle

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I just purchased a pair of jetskies. Technically one 1995 Kawasaki SS jetski with a 750cc engine and the other PWC is 1995 Yamaha Waveraider 1100. Later is running like a beast and has no issues, but Kawasaki has a problem with idle or low gas running. It chokes and feels like a strange push, like an engine skipping a beat. And unless gas is added jetski could stall on idle. However on the open throttle with higher gas feed, it runs without any issues. That possibly removes the engine issues like a crankshaft or piston ring and most likely is an issue with the carburator which i believe is aftermarket and not a standard Keihin. I just want to ask if there is anything else that could cause this issue.
Thank you for your help.