Noise level

[lmaster]

I Know, I Know, they make less noise when turned off, etc....
But sometimes the noise level may need attention.
I have a 96 Tohatsu 2 Stroke 9.9, It idles well and quiet Enough, it screams well when doing 25MPH, on a 9 ft Dinghy but in between...
If I need to travel inside the marina, at No wake 5MPH, I can either do a quiet 1MPH barely moving, little steering control or a screaming 3 , 4 or 5MPH. Anyone knows of a way to tune them for this, even if it limits other speeds? I already double coated the Cowling with insulation one layer inside and two on the outside. BTW I also noticed some air comming out of the lower cowling (is that a vent or something wrong)
Thanks!

 

[pvanv]

Re: Noise level

That's just a characteristic of a carbed 2-stroke. The old air-cooled 2-strokes from West Bend were a ton louder yet, especially at high throttle settings. If you truly need less noise, a 4-stroke is the way to go. Last weekend, I was told by someone 20 feet away that my motor was not running... I smiled, and throttled up some so he could hear it running... Such is the difference in sound level with my 4-stroke Nissan NSF9.8 compared with my old 2-stroke '72 Evinrude 9.9.

 

[lmaster]

Re: Noise level

Hi Paul, and thank you for your reply!
I am familiar with the typical 2 stroke noise, with over 30 years boating, but this one seems diferent, My other engines got loud with speed, but I have never seen one get so loud at the low rpms needed for a 5MPG cruise. I am wondering if a larger prop, or a cam adjustment would get the boat moving without it sounding like it's doing 25MPH
The other question about the air blowing on the lower cowling, Is that normal?

 

[TOHATSU GURU]

Re: Noise level

Hi Paul, and thank you for your reply!
I am familiar with the typical 2 stroke noise, with over 30 years boating, but this one seems diferent, My other engines got loud with speed, but I have never seen one get so loud at the low rpms needed for a 5MPG cruise. I am wondering if a larger prop, or a cam adjustment would get the boat moving without it sounding like it's doing 25MPH
The other question about the air blowing on the lower cowling, Is that normal?

That engine is no louder or quieter than any other 2-stroke 9.9 at the same RPM's. There is another issue of some kind.

 

[lmaster]

Re: Noise level

Thanks Guru!
It reminds me of an old Rambler rebel my parents had in the 60's the clutch was sliping and the engine reved up with little movement. In this case you do feel the power (a lot of power!) but the noise seems to start too soon...
If I put my hand near the starboard side lower cowling, I can feel some air blowing, Is that normal?

 

[TOHATSU GURU]

Re: Noise level

There should not be any air zipping around. It sounds like you may have an exhaust leak from a failed gasket.

 

[lmaster]

Re: Noise level

Thanks Guru!
Now, I know what to look for!