Propeller "rattle"

O

OUTRIGGER

New member
My boat is out of the water for the winter. On the 90 Honda I just has my aluminum prop refurbished. It is back on and snug, no givel at all. Running it with the hose attached it sounds fine in neutral, but putting it into forward or reverse I hear a irregular "clank" that I have never heard before.
I just put in new lower lube and changed the oil. Any suggestions as to what this noise could be. Thanks
 
Maybe check that the thrust washer was reinstalled in the proper orientation. If the one on my MerCruiser gets flipped it'll reduce the clearance and make a bad sound.... :shock:
 
Irregular clank. Doesn't sound like something installed wrong, but that certainly is worth a look. If something is installed wrong enough to cause a clank, then that clank should be pretty regular.

Is it possible you've got the prop close enough to the ground you are getting an occasional light "hit"? Hose close to the prop when you are forward in the boat at the controls? When you are at the back of the boat with the engine in gear, can you localize where the sound is coming from?

So many possibilities. It is also possible that you are getting a bit of pre-ignition when you are in gear and lightly loading the engine from fuel that has been sitting over the storage part of the year. Phase separation of E10 may leave very low octane straight gas going to the motor. Pre-ignition can definitely sound like an irregular clank on an outboard. AND it sounds like it is coming from the prop hub!

If you aren't seeing anything wrong with the prop install, think about some bad fuel.
 
My twins make a bit of a clunk when I shift into gear while on the hose. I don't worry about it. There is a little play all through the drive train. Not unlike shifting from neutral to drive in a car with an automatic transmission in my opinion.
 
I read the original post as after putting it into gear then the irregular clank started. It the clank is only on going into gear, I consider that normal.
 
I am guessing it to be be normal backlash it the drive train that would be held back by the resistance of the water. But I agree with Dr. Bob that it isn't a good idea to put it in gear with the prop exposed. No real harm, I guess, but no good reason to do so.
 
I did mine to make sure the cables and levers were working, after sitting for the winter. Thought it better to shift it while running.
 
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