HELP...HELP

[Pontoonman7!]

I have a 22' South Bay 2013 with a Suzuki 90HP four stroke with 190 hours with never having running issues.
Now it cranks fine, runs smooth but at full throttle dies back to idle after about one minute and then it receives a snort of gas and cycles back and forth:
I have replaced both fuel pumps and filter and plugs
Drained the tank and pulled the gas pickup and they are perfect
replaced fuel line and primer bulb and tank vent
Technician has used a gravity tank and duplicated the problem but receives no error code.
Technician has given up...
Any Suggestions????

 

[William01]

Fuel starvation issue?

When it dies back to idle drain the VST and collect the fuel. I’m GUESSING the VST will be empty or close to empty. I don’t know how much fuel should be in the VST when full vs empty so you may have to drain it when full and compare it to when it dies back to idle.

Have you checked the fuel lines for kinks, tight bends basically anything that might restrict fuel?

There is a high pressure fuel pump filter, not sure if it’s inside the VST or external to the VST.

Possibly a float valve out of spec?

Do you have a genuine Suzuki service manual? Expensive but worth the money