A carburetor valve and limiter cap assembly for limiting adjustment of fuel flow in a carburetor may include a needle valve and a limiter cap. The needle valve may have a tip, a threaded portion, a head having a flange with an outer diameter greater than the rest of the head, and one or more serrations formed on the head. The limiter cap may have a sidewall, a tab extending outwardly from the sidewall, a first cavity having an inner diameter sized for an interference fit with the flange, and at least one driving feature to engage at least one serration so that rotation of the limiter cap causes rotation of the needle valve. The interference fit between the flange and the limiter cap inhibits removal of the limiter cap from the needle valve to prevent undesired adjustment of the needle valves by an end user.