Yamaha F60 quitting

[jpack29@gmail.com]

My 2016 Yamaha F60 on my Zodiac has 95 hrs total. Recently a new problem surfaced, after 5-15 minutes at over 3200 rpm's it just quits but still idles fine. Runs forever under 3000 rpm's. Always starts perfectly. I did following- 1) Replaced low pressure fuel pump, 2) Tested high pressure pump, it was great but did not replace due to cost. 3) Changed fuel source, portable tank, new fuel, no diff. 4) Changed water separator filter, no diff. 5) Bypassed water filter separator, no diff. 6) Replaced plug just for fun. 7) Changed oil just for fun.
The water temp gage is always mid range, the stream out never seems too hot. Could high pressure pump be failing after 5-15 min? Any ideas welcome. Alternative is to pay service to haul out and fix at their shop, bids estimate at close to $1000. Can't do that. In San Diego.

[99yam40]

I would be monitoring the rail pressure when the problem shows up.
testing when the problem is not there does not help

[rejesterd]

If "it quits" means "it completely shuts off", that sounds like an issue somewhere in the fuel system. And there's lots more to check there. The on-engine fuel filer, the fuel strainer, the filter inside the vapor separator chamber, the pressure regulator, and the injectors.

If "it quits" means "it drops down to idle speed", then it's possible a control mode has been triggered (due to overheating or low oil pressure). You should get an alarm in that situation though.

[fairdeal]

yes "just quits but still idles" is incomprehensible.

"Control mode" / oil pressure or overheat alarm
is going to drop rpms, but not lower than 1800
that's not "idle"

[pstephens46]

[QUOTE=fairdeal;n223648]

yes "just quits but still idles" is incomprehensible.

Possibly “bogging at idle”?

[99yam40]

no it means drops RPM down to somewhere close to idle maybe

[Bryanzzz]

I feel your pain, had a similar problem with my 2014 F90. My problem was vapor lock due to a kink (from the factory) in the vent off the VST. Mine would crank every time cold, motor up to temp and shut it down for 45 or so minutes, fire it up, get on top and 30 seconds later it would die...like out of gas, pump primer bulb and it would crank and run fine. Did as you with a portable tank connected to motor to assist troubleshooting. When your problems occurs have you tried pumping primer bulb? Temp gauge reading OK but you may want to consider replacing water pump impeller, if problem is vapor lock new impeller could get your cooling water temp down a little. Good luck, once you track down the problem please post what you find.