Yamaha 2007 50hp stalls at 800-1200 RPM, then runs well above 3000+rpms

[yama8454]

I have a 2007 50 HP 2 stroke (3 carbs) with the following problem:
1). At idle, runs absolutely perfectly and does not stall.
2). Starts immediately
3). At WOT, runs extremely well and does not stall
4). When slowly accelerating from a dead stop to about 800-1200 rpm, the engine will stall and kill. If I hit the gas really hard from idle to get it to about 3000 RPM quickly, I do not experience the stall. This happens consistently.
Any ideas?

[99yam40]

1st Make sure you have clean fuel in tank and not some old stuff.

Next clean the carbs and then adjust according to the Yamaha service manual if the problem has not gone away by using the fresh fuel

[yama8454]

1st Make sure you have clean fuel in tank and not some old stuff.

Next clean the carbs and then adjust according to the Yamaha service manual if the problem has not gone away by using the fresh fuel

Gas is fresh. tank is new. Gas line is new. No water in gas. No air leaks in line. Since motor idles well and wot is also good, do u think this could simply b a carb adjustment? If this is an adjustment, what specific adjustment should b made?

[99yam40]

Any and every time you reinstall the carbs on the motor the link and sync procedure needs to be done, as the carbs never end up in exactly the same place and the linkage all needs to be redone. Even a very small difference in the amount of opening of the individual carbs can cause problems.
If the motor does not run properly with the factory spec adjustments, the the carbs have some blockage and need to be cleaned, readjusting them to try to overcome a problem is not the way to go.

Sounds maybe like you have some blockage in off idle ports

[yama8454]

Any and every time you reinstall the carbs on the motor the link and sync procedure needs to be done, as the carbs never end up in exactly the same place and the linkage all needs to be redone. Even a very small difference in the amount of opening of the individual carbs can cause problems.
If the motor does not run properly with the factory spec adjustments, the the carbs have some blockage and need to be cleaned, readjusting them to try to overcome a problem is not the way to go.

Sounds maybe like you have some blockage in off idle ports

Thats what I thought..Just wanted to confirm..thanking you very much 99yam40 for your quick response...will tend to this problem

[dorf]

Please Report back with the fix..thanks !!!

[yama8454]

Carbs needed cleaning

Please Report back with the fix..thanks !!!

I cleaned carbs. That was the problem