Originally Posted by monte
Hi, I notice a high pitch
noise from our new Yanmars, Starboard a little more annoying than Port, at high revs (2800-3000) Max revs is 3200 and we have been running them in as per the specs (first 10 hrs mostly at 2800, with occasional WOT for 1 minute, after that various revs, but mostly around 2800.)
Im not sure what the noise is. Maybe the blower? Its hard to tell exactly where its coming from, its almost like the start up alarm
sound from tacho, and it may be coming from there, or from the engines themselves and occilating through the hull
. Any ideas, theories, experiences much appreciated..
Engines have done around 20hrs each and saildrives are SD-60's
Frequency - If the whining follows throttle it is likely not the blower or resonance from the hull.
variable frequency - ball and roller bearings and alternators are some of the suspects in variable frequency whining - remove the engine
and if whining stops the gearbox
can be suspect. If whining continues it can be assumed to originate from engine
or engine equipment
loads with engine speed constant - i.e. shut down powered systems. Changes in whine could indicate alternator
after isolating the above you are sorta down to basic engine equipment
pumps, impeller pumps, injector pumps which all have ball and or roller bearings.
Once you get down to a certain level of isolation you may just be hearing a normal engine noise.
It would be good to be able to hear someone else's engine.
Also - did you have this boat before engine changes or is this all new. If you had before engine changes I presume you did not experience the whining.
PS - Are these turbo engines?