1988 115etxg

1988 Yamaha 115ETXG that seems to have a backfire or something out of the water. In the water it runs fine at low rpms but when I give it better than 75% throttle it Boggs down and eventually does, then it is very hard to get restarted and will not stay running. Things that have been done:

- checked for spark- it’s good
- cleaned carbs- don’t know if I cleaned them good enough
- checked compression- all cylinders between 118 and 120
- changed fuel hose from tank to bulb
- changed fuel/water separator
- checked the screen/removed screen on fuel pickup in tank
- drawing a blank on what else to do. Any help much appreciated.

Did you disassemble carbs and soak?
Did you check fuel pump pressure?
Is all your gas fresh?
Will it run better while squeezing primer bulb?
Will it run better by activating chock?

- I disassembled the carb bit did not soak, just sprayed with carb cleaner
- I didn’t check the pressure on the pump, I took it off and inspected it, looked okay but not sure how to check the pressure
- gas is fresh
- when the boat is out of the water and I advance the throttle it runs alright but when I leave it advanced it starts to die a little and the bulb goes flat, I can feel the bulb slowly flatten but when I pump it it gets hard again and runs better
- I have not tried the choke but when it does die (after it’s warm) and I pull the choke out it runs

If your primer bulb is sucking flat thats a sign of a restriction ,primer bulb to pickup tube.