Yamaha 2003 F115 hp sputters and dies at revving up

Hello Guys,
I hope you can give me some advice on the next thing to look for with the motor I have. Here is the problem. It starts up fine, idles at 1200rpm (I know it's very high), but cannot ajust it down. Quickly snap it in gears, stills idles high. As soon as I rev it up, it sputters and cuts out on me.
I've cleaned the VST tank and filter thoroughly and also the clear tank filter before the mechanical fuel pump also, all injectors sprays fine, electric fuel pump works fine, fuel rail pressure is 38-40psi. All coils produce consistent sparks, new sensor pressure, all wires are checked and retaped tightly, fuel injectors were cleaned out, no bad seals, check all sensors, fuel regulator (no fuel in vacuum line)...
The only thing I noticed is when I do a terminal test with key off or completely out of the control, I saw spark at the battery terminals when touching the terminal wires to the battery. Can it be the key ignition switch short that causes this problem? Or some other short on the boat? All Yamaha dealers and mechanics will say: "it's a fuel issue, check fuel pressure, clean/replace VST filter, fuel water seperator, etc...
To me, this is more of an electrical problem so I am checking to see if ya'll have any unique advice from your experience with this motor.
Tomorrow, I will replace the key ignition switch and will test the main relay, and will post back the result when done. But I hope one or more of you can help with an advice from your experience.
Thanks and regards,
HQ

Replaced all filters, changed over to another control box with key ignition and harness. The same problem exists. The buzzer sounds off long beep. Cut off the bad thermal sensor switch, still the same. water stream is strong and the motor seems to be warm only. Removed the thermal stat. It looks to be okay. I am heading toward a Yamaha dealership today and will post back to see if there's anything wrong with the ECU. The main relay is fine.
Doesn't look like anyone wants to jump on into this with a hint or advice....

Email me

im in your area and will fix it for ya

Justintime.
Thank you for the offer. I went thru all electrical tests again today with a Yamaha dealer manager who is a friend of mine. We replaced injectors even though they seem to work ok. We replaced all suspecting switches, replaced thermal sensor, ended up replaced the mechanical fuel pump that was told to have just been replaced. Readjusted every sensor and shift position to the Yamaha spec. Got the motor up running fine. Dropped it in the water, it only got up to 3500rpm max at WOT. Pulled it out of water, checked the lower unit. Big time water intrusion. Checked crankcase oil, big time water intrusion. F! The motor is a piece of sh! Project is done as of now $1240 and 80hrs spent on it.
Thanks all for the attention.

you want to sell the motor?

It's gone, "justintime".
I now have a '00 50hp 20'' shaft complete with excellent control. Compression was told to be 115lbs on one cylinder and 120lbs on all others at cold test. I was also told that it overheated and will need cooling system repair and possible a head gasket. $800 email me for pic and getting off this useful site on this subject [email protected]. Thanks Justintime.