Propeller "rattle"

OUTRIGGER · Posted: Tue Mar 26, 2013 10:26 am Post subject: Propeller "rattle"

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

PeterQ · Posted: Tue Mar 26, 2013 11:51 am Post subject:

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.... Shocked

potter water · Posted: Tue Mar 26, 2013 12:47 pm Post subject:

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.

journey on · Posted: Tue Mar 26, 2013 12:48 pm Post subject:

I get the same sound on the Honda 150. I quit worrying a couple of years ago.

Boris

lloyds · Posted: Tue Mar 26, 2013 1:24 pm Post subject:

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.

potter water · Posted: Tue Mar 26, 2013 1:53 pm Post subject:

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.

thataway · Posted: Tue Mar 26, 2013 8:03 pm Post subject:

Why are you putting the engine in gear when on the flushing muffs?

TyBoo · Posted: Tue Mar 26, 2013 8:17 pm Post subject:

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.

lloyds · Posted: Tue Mar 26, 2013 8:47 pm Post subject:

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.

Robert H. Wilkinson · Posted: Tue Mar 26, 2013 10:38 pm Post subject:

If you don't like clanking noises when you put your boat in gear - get a Volvo Mr. Green