Jet Drive Noise

[twier]

I just put a used 20 hp Johnson jet drive on a 14 foot Jon boat. Performance is fine. The problem I have is the noise. When I get it on plane the jet water exhaust is out of the water and the noise is very loud. The excess noise is out of place if anyone else is on the little rivers of Northwest Wisconsin. Noise is normal at idle. Any ideas? Or is that just the way with jet drives?

Thanks

 

[ondarvr]

Re: Jet Drive Noise

OB jets are loud, or at least louder than the same motor with a prop and there's not much you can do about it.

The main thing to check is the small torque tabs inside the jet nozzle, make sure they are straight and not bent.

The small tabs are located just inside the nozzle and are designed to be bent to compensate for engine torque. If you use them as designed and bend them, it can make the motor much louder.

The exhaust exits in the center of the nozzle, the water jet surrounds it and quiets the exhaust. When bent, the tabs disrupt the flow that encases the exhaust, creating gaps where the sound escapes.

 

[twier]

Re: Jet Drive Noise

Many thanks. I will check the tabs.