I have an older scag 48" walk behind mower with a new kohler 15hp comand pro engine (10 hrs on engine). Pull start. Will not start unless I remove spark plug and shoot gas or starter fluid in cylender. After trying tp start I remove plug and its dry which leads me to believe its not getting gas. Choke is fully closing. Will not start by shooting starter fluid in carb...must go into cyl. Once it starts runs great. Any ideas?