'03 F115 TLRD Shuts Down!

[tanfish]

Went out last week and the motor shut down after 20 mins. running 4500 RPM.
Would not start, got towed. Got home it started. Next day started again but
shut down after a couple minutes. Mechanic came 3 days later and it ran w/no
problems, computer diagnostic showed no problems. As I explained to the
mechanic only way she started was when I unplugged the temp sensor. She
would run for 10-15 secs and shut off again wether sensor was plugged or
not. He said coincidence that it was starting so. Came to possible conclusion
high pressure pump screen was clogged. Spent 4 hours Sunday, removed HP
fuel pump, inspected and cleaned screen which was not that bad. Went out
this afternoon and she shut down 200 yds. from the dock, towed by good
samaritan. She's been starting and running since the mechanic came and
after I disassembled the HP fuel pump. Some suggest kill switch or even key
switch while others are stumped! I did find sort of a gummy substance on the
valve on top of the fuel rail which I'm wondering where it came from.
We did press on the valve to let fuel out and see if there was fuel in there.
Could this gum like stuff have come from there? Could the rail and or
injectors be getting clogged w/this crap? Any ideas would help!!!
I'm stumped!!! Thanks in advance!

[99yam40]

checking fuel pressures will help in troubleshooting

[tanfish]

Thanks, someone else told me the same thing. That's where I'm going next.

[tanfish]

Well, I finally solved the problem and as was said by 99yam40 checking fuel
pressure is what did it! I hadn't checked previously for two reasons, a wanna
be mechanic told me that the HP fuel pump either works or it doesn't,BS!
The other reason is that I had to find someone with a fuel press.gauge and
that took a little time. After installing the gauge on the rail the pump was
measuring 38psi instead of the 44psi as per the Yamaha specs.
Started the motor and it ran for about a minute and shut down when the fuel pressure
dropped to between 0 and 10psi. After installing the new pump she's running
like a champ again! Thanks to all those who helped! I hope this write-up might
help someone else one day if they come across a similar problem. By the way
the pump failed at around 290 hrs. and I spoke with someone else today that
had the same problem. His failed at around 230 hrs. of operation.