I looked at the manual and it said nothing about throttle at start up. What I thought was a inline filter looks to be a electric fuel pump I think? Their is a wire running out of it. I looked up racor's and they should have check valves in them. I don't see any thing else that looks like a check valve. I checked every hose clamp and seemed a little loose but she still starts the same. Will run for a second or two and then die. Until you use the throttle. I am going to check the in line fuel pump and look for a check valve.