Yamaha Generator Oils and Running In / Break In

There is a great, and comprehensive response to this common question at the Yamaha Generator Fan Club here:

kroman, The temptation is to put a premium synthetic oil in it for the break-in, but you should NOT use a synthetic until the engine is broken in which is AFTER the 1st manufacturer recommended oil change time interval. If you use a Synthetic oil on day-1, it will delay/suspend the moving/rotating/sliding parts microscopic hone-in required for the break-in!

For regular petroleum oil the newer rated oils, alphabetically beyond "SH" (as in SJ, SL, SM) had friction modifier (AKA "reduction") ingredients progressively removed from the ingredients because they were found to coat-n-clog the catalyst medium, damaging it's function. That's the main reason to use the Yamalube recommended for power equipment. You can get SH rated oils in straight weight, like 30HD (HighDetergent) in auto parts and HomeDepot type stores and sometimes multigrade (10W-40) in MotorCycle oils for bikes without a catalytic converter (Harley).

To fill my EF2000iS or EF1000iS I use a funnel with the Genny tipped away from me by way of a length of 2 x 4 stud for a 2" rise under the open side rubber feet. Then slowly add an amount of oil LESS THAN the specified amount so I can remove the empty funnel with a paper towel underneath to quickly transport it to the oil bottle's opening, then remove the wood piece and see how high the oil level advances up the threaded hole. From there, add the board and fill small amounts, removing the funnel-n-board for level rechecking each time. It takes longer than pouring and making a mess, but cleaning up that mess that goes in-n-under the motor outta' sight takes a lot longer and leaves behind a dust attractor and a "hot oil smell" when you open it up to drain the carb floatbowl. The funnel/board/papertowel trick doesn't spill a single drop, but you must be patient and use good judgement.