I have a 2007 2-stroke yahama 50 with 70 hours. i’m having trouble with the motor stalling when attempting go on plane. the motor starts, idles and trottles up fine in nuetral…i’ll spray carb cleaner and the motor will run and plane out great until we idle or stop again…i use a stabilizer, changed the fuel/water filter, changed the fuel lines and primer bulb…need help please…
If you figure it out let me know. I hav the same motor and same problem. Seels is backed up 3 weeks for service so I’m high and dry.
“Fishing is not a matter of life or death. It’s much more important than that!”
From a great net article:
http://unitedboaterscoop.com/html/outboard-fuel-systems.html
If you suspect the motor is not getting fuel (assuming that squeeze bulb is in proper condition and operation), first check to see that all hose connections are tight and not leaking air into the system as it attempts to draw fuel from the fuel tank. If all looks ok, next run a quick compression check on the the cylinder that controls the fuel pump. A low or 0 compression reading can show cause for a “starving for fuel” condition. If compression checks ok, its probably a sure bet that the fuel pump diaphragm is worn or punctured. Remove pump and inspect diaphragm closely.
Tidewater 196DC
Yamaha F115
Pungo 120Seems like a new motor to have a fuel pump diaphragm go out already. Did you use a Yamaha OEM primer bulb? I’ve used a aftermarket one on a F150 I used to have and it caused problems. Switched to the Yamaha and had no more problems. Could have been coincidence. Is primer bulb staying firm? If it’s going flat it’s losing prime and no fuel is getting to the engine.
Also, is it on a new boat or an older one? I had the check valve in the top of my 95 Keywest’s fuel tank fail. It would stick and restrict fuel. The boat would die about 1 minute after up on plane, everytime. They get old and corroded.
you have crud in the carb
when you get it to turn higher rpms, its pulling higher vacuum, and its able to pull the fuel
that means you are running your motor lean, so please stop doing that, and have it fixed, so we dont have to read about you needing a new motor
I’m now at www.teamcharlestonmarine.com
Can you fix it or are yall three weeks out also?
“Fishing is not a matter of life or death. It’s much more important than that!”
Oh and by the way, you won’t be reading about me needing a new motor you will just have to come visit me in the surf/pier forum cause I won’t be able to afford a new one 
“Fishing is not a matter of life or death. It’s much more important than that!”
Update…removed and inspected fuel pump diaphragm…had no holes or tears. removed and cleaned carbs…had no crud and grime, but cleaned anyway… reassembled all and starts fine…put it creek and still stalls under load…i’m at a loss for ideas…i’m thinking that there is an air leak or restriction in the fuel line but i can’t find it, so where do i look and how do i tell? primer bulb(not yamaha) and fuel water separator are new…keep the suggestion comin’ cause i got 3 weeks before a mechanic can see it.
I would just replace the entire fuel line if you think that’s what it is. Thats pretty inexpensive. Also, the first step in “fuel delivery troubleshooting 101” is to run it on an external tank to eliminate all of the issues you’ve already looked at.
Chris is well respected here, and I’d take his advice about continuing to run it. Run it lean like that too many times and your going to score a cylinder.
Update…removed and cleaned the 3 carburetors for a 3rd time and finally got the motor runnin’…kudos to Chris V for the online diagnosis…i believe the bypass jets on the top of the carbs were the culprit…bought a rebuild kit cause some of the o-rings gave me trouble the second time i cleaned the carbs. Thanks for all the help and info.