Air filter
 

I'm having a problem with my 250 4 stroke Yamaha it's a 2006 it won't stay running hard to start bogs down and shuts off , what should I look at ? Thanks for any replys

fuel pressure or water in fuel,

I will check the fuel water sepperator first but how do you check the fuel pressure?

fuel pressure gauge, have to have one that screws onto the fuel rail. Check compression on the cylinders while you're at it, look at the plugs, see if any of them look different that the others