Merc motor question

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Larry Gregan

Well-Known Member
Apr 5, 2001
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First of all thanks to those who helped with my last questions. I am pretty new at boat ownership so any advice is really appreciated. I have a new Nitro 750NX and it came with a Mercury 75 2stroke. I started it up in my driveway for the first time with the garden hose and engine muffs. It sounded like the engine runs a little rough and also sputters. I'm not used to a big engine so I am not sure what to listen for. Is this normal for a new motor? I know the dealership also put a special mixture in the gas telling me since it is new it needed it. They also advised not to go over 3000rpm for the first ten hours. I can't wait for the maiden voyage and hope the motor runs smoother in the water. Thanks and this is a great web site.
Big outboards make a heck of a racket out of the water. The exhaust is thru-hub, in other words, its like having a straight exhaust out through the prop. Imagine a car with no muffler and headers. That is what it is like. When you sumbmerge the lower unit in the water, you will find your motor to be very quiet, and you won't notice the rough sound, it will be very smooth. ENJOY!!!
Tom Richardson ... Thanks I'd hoped there wasn't anything wrong with a new motor. Like I said I am new at this boat ownership thing. Next big challenge will be loading and unloading at the ramp. Thanks again. Larry
Larry -

Having the hub in the water will also give a bit of back pressure to the exhaust flow..... 2-Strokes need that to run smoothly. It will help eliminate the rough "Popping" sound you hear when the motor is running out of the water.

You'll like how quiet the 75 is. I can carry on a conversation with whomever is setting next to me in a normal voice. Good fuel economy too.

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