yes you can adjust the mixture on the carb. has your grizzly ever had the valves adjusted that will make your grizzly hard to start when cold and it wont run right.and if you adjust your valves you will get a different reading on the spark plug.here is some oil filter numbers k-n-303,fram-ph6017a,napa-1358,ac-2057,wix-51358,amsoil-smf-103.