I just bought a boat with a 2004 Yamaha 200hp 4stroke motor with 20 hours. Everything checked out when the boat was surveyed and motor inspected. They even did a computer scan to confirmed hours, and normal compression test, etc.
During the first time using the boat, I heard a thumping sound while I was docking. It was a sound similar to what my 2 stroke motor made when it "rattled" at idle, but this 4 stroke has no rattle (nice and smooth). It doesn't sound like a metal to metal grinding, more of a thump at a rate of 200 times per minute. It doesn't always happen and there isn't anything specific that I can do to cause it.
Since I'm new to 4 strokes, I'm wondering if this noise is typical with 200 hp 4 strokes or should I be looking further? I know the motor was winterized prior to a northeast winter storage, but I have very little additional service info. I'm also assuming the fuel (ethanol free) has been in the boat for 2 seasons.
During the first time using the boat, I heard a thumping sound while I was docking. It was a sound similar to what my 2 stroke motor made when it "rattled" at idle, but this 4 stroke has no rattle (nice and smooth). It doesn't sound like a metal to metal grinding, more of a thump at a rate of 200 times per minute. It doesn't always happen and there isn't anything specific that I can do to cause it.
Since I'm new to 4 strokes, I'm wondering if this noise is typical with 200 hp 4 strokes or should I be looking further? I know the motor was winterized prior to a northeast winter storage, but I have very little additional service info. I'm also assuming the fuel (ethanol free) has been in the boat for 2 seasons.
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