04 yamaha 115 4 stroke

[Skishop01]

Does any one no if yamaha 4 stroke engines are prone to fuel vaper lock after a long run time? My engine runs great when you first start it up, but after a long run it will not start back up for about an hour. The engine turns over fine but will not start and run. Thanks.

[rodbolt17]

vapor lock in an EFI system is almost impossible.
however an over rich A/F mix due to perculation in the air box can and does happen.
try cracking the throttle slightly.
if that helps a hot restart look for how and where the VST is venting vapors in the air box.

[pstephens46]

Works every time! Assuming you know how to open throttle in neutral....

[boscoe99]

If Yamaha did not use a VST and vent fumes therefrom back to the intake system none of this silliness would happen.

[Skishop01]

I removed the vst and serviced the pump found nothing wrong. Also installed a new needle and seat. Sorry, forgot to let you no the throttle body seemed very hot to me.

[pstephens46]

If Yamaha did not use a VST and vent fumes therefrom back to the intake system none of this silliness would happen.

Wonder why some have issues and many do not?

[rodbolt17]

the throttle body will be about engine temp.
venting to the air box was not Yamaha's idea.
thank the EPA.
three ways to vent it,through the intake.
overboard.
under the cowl.

[Skishop01]

Thanks for the help, i will look at it again this week. Will keep you posted on what i find. Thanks.