2001 0x66 225 intermittent starting

[73makocenter]

I have a 2001 225 0x66 yamaha outboard. Engine starts initially EVERY time, once it has run for a while and you shut it off it may not start. It will turn over and over, but won't start. Sometimes first attempt, fourth, eighth, you never know. If you allow motor to sit 5 minutes still won't start, 10, nothing, wait 20 minutes or more it fires right up!All 100 services have always been done at my Yamaha dealer since new. It seems as though when you hear to fuel pump buzz(20 seconds or so) it starts everytime. Of course that is always on trailer at the house! Only when on the water does this take place. I have been to Yamaha,(a five star repair dealer) they can't get the motor to repeat this issue, therfore unable to offer any solution. No matter how many times you try to get engine to repeat this so you can trouble shoot it, it starts every time! One sure way, is to get out on the water, now it will do it! I replaced my 3 diaphram pumps, thought I may have had it figured out 3 trips no problem. Then back to above problem, motor runs perfectly when running, no performance issues at all. O2 sensor clean vsr clean any ideas? Thanks for any help you may offer.
73makocenter

[too tall]

same problem

I Have A 2007 Z20 Ranger Does The Same Thing It Will Start Every Time For About A 3 To 4 Hr Time Frame Then When You Punch In The Code On The Touch Pad It Will Turn Over But Will Not Start When You Wait 20 Min.it Will Start. Called Ranger Saidnot A Touch Pad Problem They Said Sounds Like Ecu Unit.now It Will Shut Down When You Come Out Of Hole And Get On Pad At Wot.if You Just Ease Out Of Hole It Will Do Fine. I Need Help Too.