Yamaha 15hp 2 stroke stalling on throttle advance

[pritch]

I have a Yamaha 15F 2 stroke, that starts and will idle OK but when throttle advanced engine stops. Spark advances OK at this stage.
Is this just a fuel problem?

 

[robert graham]

Have the carbs ever been removed and cleaned?...sounds like a plugged carb jet to me

 

[pritch]

Yes have stripped and cleaned carb and fuel pump, but can do it again.

 

[robert graham]

That's probably your problem.....maybe install a fuel/water seperater /Walmart/Attwood unit is $25).....easy to install and great preventive maintenance so this won't happen again....use Stabil in your gas tank all the time...

 

[pritch]

Thanks Robert

 

[pritch]

This motor also backfires when advancing the throttle and spark. Cleaning all fuel lines, carb, and filter bowel have not made any difference. What would be causing this symptom ? Help.

 

[robert graham]

I don't know about that one but hopefully one of the gurus on here can offer some ideas for you....

 

[racerone]

Start with a model # or pictures of the motor.-------Would a 15F be a 4 stroke ??

 

[pritch]

The motor is a Yamaha 15hp 2 stroke ( 15FMH 684K / S / 1035290 N

 

[Sea Rider]

When doing that will OB spit fuel backwards of carb ? Being a 2 stroke OB could be doing that due to a reed valve related problem ?

Happy Boating

 

[pritch]

That is hard to tell with the air intake covered. Could it be a timing problem?

 

[racerone]

Timing on modern outboards does not go out of adjustment.-----But the flywheel key could be sheared and that does change timing.----I would check the key, it is a " no money spent " procedure.

 

[robert graham]

Does that motor have a linq and sinq procedure to set timing with carb linkeage after carb removal?....if so, it's in the manual...

 

[pritch]

Yes I am looking at the manual now and will check the timing settings in accordance with manual requirements. I must admit that I have had the flywheel off and assumed that it aligned with the key when I replaced it. I will check it again. This motor has been going fine for the last 14 years until it blew the charge coil and CD unit which both have been replaced.