My 1999 175 Mercury SportJet was running fine up until the last time out on the river. Engine started fine and ran good at high speed but after shutting off the engine for a while to fish. It was hard starting and kept stalling after starting and leaving in idle. Replaced the anti-siphon valve, fuel filters and tightened all the clamps on the fuel lines.<br /><br />Engine will idle while it is cold but after it is warm stalls within a couple seconds of slowing down to 1000 rpm. While testing I removed the carb cover and the engine ran fine even after being warmed up. Any suggestions as to what to check next will be appreciated greatly.