Search here in fuel related areas, get the fuel system in top notch shape before you burn the motor from lean overheating, any part of the fuel system can allow air to enter which will cause the motor to slow down, and if the filters are not cleaned and sealed the same symptoms develop, this is very common for the 90's 2stroke family - yearly and new 2 you maintenance will be to clean out the fuel filters in the carb inlets and flush thru any steel gas can trash or other such swarf to insure the motor will have clean flow of fuel, a very basic idea that works well for most of the mariners is to dip on the side ramp and leave the boat on the trailer - start the motor with the pump in the water - feel the cooling hoses for warmth - observe any fuel/oil/water leaks, you can check the battery charging system at the battery posts by lifting the throttle a bit to get all the juices flowing, if you go to the parking lot to fix something dip again and test it, if you go home be sure to blow out the motor with a few quick blasts of the throttle with the pump out of the water - when you do this you will stop a lot of breakdown drama and your trips to the water will be much more smiles per gallon.