It's very possibly/probably is running lean and if my dispute with returning the engine doesn't work out I probably will go that route. I just think it is a shame that out of the box it doesn't perform to the manufactures own specifications.
As said above I would love to test the 4hp 5hp engines against the 6hp. My understanding is that the engines themselves are identical. I have been told that it is only the jets that are different in the carbs. I have also been told that they are different carburetors on the different models. But the manufacture themselves will tell you that other than something in the carburation being different that the engines are identical for all three models.
I had actually had the thought at one time that my engine mistakenly got jets for a 4hp engine in it. However since testing the second 6hp engine and getting the same test results I no longer think that is likely.
Last edited by audeojude; 10-02-2007 at 04:05 PM.