Yamaha 15hp 2 stroke stalling on throttle advance

pritch

Cadet
Joined
Dec 23, 2018
Messages
13
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

Admiral
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Apr 16, 2009
Messages
6,908
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

Cadet
Joined
Dec 23, 2018
Messages
13
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

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Apr 16, 2009
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6,908
I don't know about that one but hopefully one of the gurus on here can offer some ideas for you....
 

racerone

Supreme Mariner
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Dec 28, 2013
Messages
36,047
Start with a model # or pictures of the motor.-------Would a 15F be a 4 stroke ??
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
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

Cadet
Joined
Dec 23, 2018
Messages
13
That is hard to tell with the air intake covered. Could it be a timing problem?
 

racerone

Supreme Mariner
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Dec 28, 2013
Messages
36,047
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

Admiral
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Apr 16, 2009
Messages
6,908
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

Cadet
Joined
Dec 23, 2018
Messages
13
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.
 
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