Re: 75 hp Yamaha Stalls when slowing to nuetral
Been working on my 90 lately and have had to rebuild the carbs (clogged jets) and replace fuel pump. Fuel pumps rarely go out all at once, but start giving tell-tale signs. They are not expensive and easy to change, if even to eliminate the issue.
Check the filter beside the pump, mine had bits of black (surely hose bits from ethanol degradation)
If you do not have a water separating filter, install one. Usually recommend a 10 micron filter.
If you have an electrothermal valve (you did not say what year) check it for proper operation. It is an electric solenoid on the center carb. It feeds extra gas for priming/start up, and if not operating properly could be giving you a rich condition at low throttle.
Look for any loose fuel lines etc. You can also pull the plugs to look for a lean or rich condition.
Check plugs or replace.