Hard start, will crank and run only with choke

I’m having the same issues. Hard start, will crank and run only with choke wide open only then suddenly dies. Adjusted valves, new starter gear (slightly worn…possibly the numerous times trying to crank it), when preparing to adjust valves, I can hear the cam mechanism click when exhaust valve reaches dead center. Only option that I have left is new spark plug, fuel filter, check choke position to ensure it’s operational and give it a good washing. This sometimes it’ll crank easily or the continuous issue of it’ll start today or not is difficult to pinpoint the exact problem is beginning to be a nightmare.