For example, tell me:
* What type of engine is it? (Car, motorcycle, boat, lawnmower, etc.)
* What kind of fuel does it use? (Gas, diesel, etc.)
* What are the symptoms of the bogging? (Stalling, lack of power, sputtering, etc.)
* When does the bogging occur? (When accelerating, at idle, under load, etc.)
Once I have this information, I can give you more specific advice on how to get your engine stop bogging.