Hittng rocks with prop at 5000 rpms, 75 4-stroke

[AKblackcod]

I hit some rocks and knocked off a lot of all 3 prop blades cruising at 5000 rpms. I immediately backed off gas and the motor was vibrating so I came to port on my kicker. After replacing the prop the vibrating stopped and the boat ran normal for about 5 hours then the motor started making an intermittent clicking or popping noise, again I came in on my kicker.

The motor makes the noise when not in gear so I don't think I damaged the lower unit.

Could the rpm's have gotten high enough to damage my motor when I knocked off the prop blades? I didn't look at the tack after I hit the rock.

Thanks,

[rodbolt17]

nope.
the rev limiter will grab it about 6200 RPM.
you most likely bent a propshaft and its leaked oil or some internal case damage.
or it could be a totally non related issue.

[millennium]

S/steel prop if so marking on ur lower dogs and makes bad sound ???? Dont know but thats one thing and box is full time.

[AKblackcod]

Thanks for the come back, I felt better knowing I didn't damage the motor.

I took my motor in to the Yamaha dealer and unfortunately you were correct rodbolt, the prop shaft was bent, broken teeth and bearings shot. The whole lower unit needs rebuilt or replaced.

Another expensive lesson. Pay close attention to your charts and the tides......