2001 Yamaha 200 HP HPDI noise

[jstavrakas]

I have twin 2001 Yamaha 200 HP HPDI engines on my boat. Last October, I noticed they were making a different noise when I ran the engines up at 3500 rpm and higher. It was kind of a ringing noise but could also be like valves tapping or knocking at high rpm. The engines sound OK at idle. I had a mechanic tune the engines up during spring outfitting (as well as change the water pumps, etc.). He did not notice any problem. Yesterday, when running the boat in the morning, the engines sounded as normal with the noise as mentioned. In the afternoon, the noise was loader and more of a concern but there was a 20 knot tail wind which I guess brought the sound back to me stronger. My mechanic felt it was probably that the engines just sound different as they age and "break in". Could that be the case? I would hate to dump a ton of money into chasing a ghost... Since both engines seem to be making the same sound, could it be just that I have put another hundred or so hours on them??? They have plenty of power and start easily.

Any feedback would be much appreciated.

 

[Lundman]

Re: 2001 Yamaha 200 HP HPDI noise

That engine is a two stroke DI motor,...I can't see where you would have valves tapping or knocking. If it were four stroke,then that would be a possibility,...but not on a two stroke DI motor.

 

[jstavrakas]

Re: 2001 Yamaha 200 HP HPDI noise

Any ideas on what would cause the noise described above? I have scheduled to have a technician out on a test run but he is not available until July 13th.

I plan on running the boat quite a bit over the next week or so and will keep an ear/eye out for trouble but continue to be concerned.

Again, the engines have plenty of power and no real vibration problems but an ounce of prevention is worth $10,000 of cure!

 

[Ray Neudecker]

Re: 2001 Yamaha 200 HP HPDI noise

You might try a search. I vaguely remember rodbolt posting on a belt or pulley problem that produced a noise similar to what you are describing.

 

[yamamarinetech40]

Re: 2001 Yamaha 200 HP HPDI noise

How many hrs. on engines? Original belts?

 

[JUSTINTIME]

Re: 2001 Yamaha 200 HP HPDI noise

it is your o2 sensor if u hear like valves tapping