Chattering sound coming from v-drive

[DIESEL]

Checked the oil, no light came on...it only does this when the throttle and trans is barely engaged and the boat is barely moving. Once you pick up to 3/4mph it goes away. Any ideas what it could be?

[mndanielsncsu]

I don't know the answer, but my 93 Sport does the same thing. If it's in gear, but barely moving, it has a clatter (?) sound... don't know how to describe it. Not a grinding sound, but almost like somethings loose and rattling.

[bchesley]

Mine does that too. I think that it could be the prop. If you look at some of the newer (I think 2000 and on) SS and Sans they have a stainless steel plate on the rudder to hull mount. They did this because of turbulance caused by the prop being so close to the hull. The turbulance will over time eat away the gel coat at the prop mount .The factory 14x18 prop is even closer than the newer models. I had always thought that they started using the shorter props (13.5 instead of the 14) and putting the plate on to stop a cavatation affect. I am only guessing that this sound could be from that.

[Erik]

bchesley and others - does it seem like every time this topic comes up (and it comes up a lot) there is a different theory floated? If it is a Super Sport, the v-drive's are quote - "bulletproof" - and my dealership says replacement/rebuild is exceedingly rare. I've asked them to look into the chatter at low rpm's twice now and they say it is normal behavior. I don't like it, but I've learned to live with it.

[bchesley]

Yes on the theory. I spent some time with a 16yr PCM tech in my boat to try and figure it out. My theory is only legit if the newer boats that came from the factory with the smaller prop and the stainless steel plate dont do it.

As for living with it. My tech said drive it like you stole it, its a nautique........

[DIESEL]

Well, come to think of it...I never heard this sound till I went from a 344 to a 1464 prop.
But it doesn't do it all the time. That's what baffles me, I even checked the water depth when it's done it and they have been shallow and deep areas when it's happened.

As for living with it. My tech said drive it like you stole it, its a nautique........That's the game plan!

[jmo]

Funny you should mention that as I recently started hearing the same thing at the end of last season if I just ever so slowly nudged the boat forward into gear. I had it checked out by a correct craft tech and they couldn't find anything wrong other than I was due for a transmission fluid change (it was full).

While I was there I had them upgrade me to a newer prop (acme 380) and it turned out the castle nut came off by hand and the prop just came right off without a puller! - the tech said the prop not being on tight enough could have definitely been the culprit for causing the backlash noise in the transmission on slow take off.

Since switching the prop out the sound is gone!

hope this helps...

[DIESEL]

I'm checking my prop as soon as I get off work.