I have a 2003 Yamaha F115. Over the last couple of years it has been developing a problem with hot starts. The motor always starts when cold, when it has been warmed up and is stopped for more than a 5 minutes or so (but not cooed down) it will crank (at normal cranking speed) but will not fire.
The problem appears to be related to fuel supply (or lack of) as if I spray some fuel in the intake it will fire.
Compressions are all even 160-165psi.
Minimum voltage under cranking is 8v+
Fuel has been run direct with no change in behaviour
New high octane fuel makes no difference
Manual Priming prior to cranking makes no difference
Advancing the throttle during cranking makes no difference
Cooling water is flowing through the fuel cooler
I have not done a code check, but no flashing or warnings shown.
When running fuel rail pressure mid 20's, have not had reliable reading when in no-start condition (don't have proper guage).
When I turn on the ignition for a hot start I usually hear one or two things. A brief hum (which I presume is he HP fuel pump?) and a brief chatter (idle control valve?). I have noticed that when it is not going to start it does both. When it is going to start I only hear the hum....
Can reliably be re-stared with spraying fuel into intake so some form of fuel starvation suspected.
Any thoughts?
The problem appears to be related to fuel supply (or lack of) as if I spray some fuel in the intake it will fire.
Compressions are all even 160-165psi.
Minimum voltage under cranking is 8v+
Fuel has been run direct with no change in behaviour
New high octane fuel makes no difference
Manual Priming prior to cranking makes no difference
Advancing the throttle during cranking makes no difference
Cooling water is flowing through the fuel cooler
I have not done a code check, but no flashing or warnings shown.
When running fuel rail pressure mid 20's, have not had reliable reading when in no-start condition (don't have proper guage).
When I turn on the ignition for a hot start I usually hear one or two things. A brief hum (which I presume is he HP fuel pump?) and a brief chatter (idle control valve?). I have noticed that when it is not going to start it does both. When it is going to start I only hear the hum....
Can reliably be re-stared with spraying fuel into intake so some form of fuel starvation suspected.
Any thoughts?