Hi Paul, to be able to give you the best advice, could you please upload some pics of your Jetfast.(Instructions on how to upload photos are in the Board Help Area on the main forum page) This will help identify your particular model and aid in problem diagnosis.
Re the Honda G100 engine, I have one on my Scott Bonnar Model 45 cylinder mower, they are a great motor and a strong little engine for their size. If the oil is really black, it sounds like it has not been changed for quite a while and /or the engine has done a lot of work.
Firstly, get yourself some good 4 stroke oil.(I personally use Honda 4 stroke motor oil,but any good
4 stroke oil will do. Not car engine oil, as this type of oil is not suitable for the Honda.) Now with the edger on a level surface, top up the oil so that it is at least up to the threaded portion of where the oil filler plug screws in; (the reason there is 2, is so this engine can be used in many different applications) Start the engine and run until it is good and warm. Grab something to catch the used oil and a suitable spanner for the oil drain plug (underneath the oil filler plug) Stop the engine,remove the drain plug and drain the oil. When that is complete, replace the drain plug, and refill with oil to the correct level immediately, because if we leave it till later you may forget and start it with a dry sump....Not good!
Secondly, check and replace the air filter element if necessary. Dirt and dust is the enemy of outdoor power equipment.
