It’s a SX200tXRY.Is it an OX66? Does it die like someone turned the key off? Will it restart without issue after it sits for a few minutes?
If the answer was yes to these questions, check your fuel pump to see if it has power the next time it quits on you. If it doesn’t, your fuel pump relay is on its way out.
Take a look at the bulb to see if it has collapsed. That would indicate a blocked tank vent usually. Also when you squeeze it, see how it feels. It should get firm normally.Next time it goes into "reduced rpm mode", leave the throttle where it was before it slowed and have someone start pumping the primer bulb. If the engine comes back to life while pumping but dies away after a bit of not pumping, then it is likely a weak primary low pressure fuel pump that is bad. Needs to be replaced.