Clunking Noise at Low Idle

[JaSla74]

Spent the day on the water & when I got home to flush the motor I noticed this noise at low idle in forward or reverse. You can't hear it at higher rpms, neutral, & everything appears to shift smoothly. The noise however is concerning. Yamaha 115 4-Stroke

 

[99yam40]

Heavy SS prop will make that kind of noise at idle in gear

 

[JaSla74]

Thanks 99. After doing some research that sounds like what it is. I've had the boat only a few months & although I haven't had it out that much this was the 1st time I noticed the noise when flushing.

 

[boscoe99]

Referred to as prop rattle or prop chatter.Doing no harm, it is just an annoyance. As 99 Yam says it is more prevalent when a large heavy propeller is used.

Both Yamaha. Mercury and other propeller makers offer props with different hubs that can mitigate this noise plus the clunking when going into gear noise.