Yamaha vf115 ran fine first day, second day stopped and won't start

[Mike_hrl]

Engine started and ran fine for the first ride of the season, second outing it died suddenly after 20 minutes and would not restart, had to be towed in. It turns over and almost starts but sounds like it needs gas. Diagnostic software says incorrect shift position switch signal. Also showing throttle valve opening should be 0-90 but with highlighted in red showing value -10.5. I changed fuel filter and water separator, oil and lower grease, it did not give any alarms while running at the time it stopped. Looking at forums and it doesn't seem to be a common problem. Any help would be appreciated before taking it to the dealer.

 

[99yam40]

being a 4 stroke maybe the timing jumped, check compression & spark
then fuel rail pressure

 

[boscoe99]

Why not fix the incorrect shift switch signal before anything else is done?

 

[Mike_hrl]

Why not fix the incorrect shift switch signal before anything else is done?

It was only running around 3000 rpms when it quit so I doubt it jumped time. Are you suggesting I replace the shift switch as a start? That was my first thought-- but how would a negative reading (-10.5) come up for the throttle opening? I was wondering if I should start with the sensor or the switch. Sensor is around $160 for the part.

 

[boscoe99]

It was only running around 3000 rpms when it quit so I doubt it jumped time. Are you suggesting I replace the shift switch as a start? That was my first thought-- but how would a negative reading (-10.5) come up for the throttle opening? I was wondering if I should start with the sensor or the switch. Sensor is around $160 for the part.

I am not suggesting that the switch be replaced. The switch may be just fine.

I am suggesting trouble shooting and then doing whatever needs to be done to clear up the code 28 for the incorrect position switch fault.

Then see if the throttle opening message goes away or not.