Bought a 1989 20 SF w 2001 200HP Yamaha HPDI.What a nightmare the engine started out to be. Finally got my boat back from the shop. After I went thru everything I could possibly think of on the motor. Filters, plugs, fuel lines, drained fuel tank, O2 sensor, and much more. Ran diagnostics- pressure in high pressure pump would be at 700 psi then down to 200 psi, Turns out the High Pressure pump filters were clogged, some very loose bolts, some bolts in places they shouldnt be. Took boat out and she ran like a scalded cat. GPS was showing 47 mph as I was headin back into Port Everglades. Needless to say I am happier than a pig is S***. Will post pics of boat soon. Thanks everyone for your help.