new 2015 25HP hesitates at high RPM

[astshop]

Hi List,
I purchases a brand new 2015 25HP 3 cyl about a month ago. I followed the break-in to the letter.
I noticed that if I put it in neutral and rev up the rpm, it starts "hesitating" (not sure how else to describe it)". Basically, it behaves as if I am decreasing and increasing the rpm repeatedly (but I am not).
In gear, this doesn't happen the engine is just fine.

Anyone has see this? Is this normal? The engine is under warranty but I am not very close to an authorized dealer.

I shot a video of this (it is very short, please listen to the sound as I increase the rpm).

http://youtu.be/p6wNRu5sUNU

Thanks,

[Solarman]

First of it is probably normal. The motor is protecting itself from the owner, who should know NOT to rev up the motor so high in neutral, without a load on the prop. It's not made for high RPMs in neutral.

[Moonlighter]

Yes, it is completely normal, and as stated above, it is NOT GOOD PRACTICE to rev any engine excessively in neutral. With modern engines, you don't or shouldn't need to rev them even when they are cold, because they are smart enough to adjust mixture etc themselves.

What you are experiencing is the classic example of the engine's self-protection system at work, it is limiting the revs of the engine in neutral so you don't damage it.

Most modern engines do this by limiting fuel supply, interrupting spark and retarding advance, or some combination of these things. Yours sounds very much like the spark interruption.

[astshop]

Thanks a lot for replying.