4 stroke 90cc will not run with choke off unless you keep it rev up?

If a 4-stroke 90cc engine won't run without the choke on unless you keep the revs up, it likely indicates an issue with fuel delivery or air-fuel mixture. The choke enriches the mixture, compensating for a lean condition, which could be caused by a clogged fuel filter, dirty carburetor, or vacuum leaks. Additionally, check for proper ignition timing and ensure that the spark plug is in good condition. Addressing these issues should help the engine run smoothly without the choke engaged.