If your outboard is going to WOT then losing power shortly after then that's most likely your issue. If your able to pull back on the throttle to half or less and power returns then it means more fuel is leaving your vst tank than can be replenished when more demand is called for. When applying less throttle not as much fuel is needed. Meaning the fuel can't enter because air(vapor) is filling it. The diaphram in the vapor pump gets hard over time and no longer works to do its job. You will notice that the vapor pump rebuild kit is also a fuel pump rebuild kit depending on the configuration.
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