45 yr old montgomery ward 26 in self propelled crosby rear wheel drive high wheel 5 hp commercial/industrial cast iron cylinder

[old guy that been around]

this was bought 1974 at Wards bargin basement for $80.oo and runs like a champ. only lately it has issue starting. the throttle control / choke isnt working as it should unless you hold ur hand to block off the air filter. with ur palm. what else could it need a throttle cable. a butterfly. float or needle valve or o rings n jet? any advice for a old man is appriciated