Strange whining sound at engine cut off - thoughts?

[gsg900]

Ok Hunter folks - long time lurker, first time poster.

Tried to search the forums for some solutions but couldn't find much. It may be out there, but the way we all uniquely describe things I could have possibly used the wrong "terminology"... been known to happen.

I've been having some battery issues (not charging at idle) that led me down this rabbit hole.

After starting up the engine and noticing the battery light stayed on, I started to notice a very faint ping or metal ratting coming intermittently from the engine at idle on the dock. Once I shut it off it made a sound like noisy brakes on a car coming to a stop.

Youtube video attached. Apologies for the short length, you will notice the high pitched sound (short) before and after me yelling "go for it" for my assistant (thank you fine neighbor) hitting the engine kill switch.

Any thoughts? With the impending weather in the NE I'm not leaving this week anyway, but I'd like to get her shipshape soon...

And thanks in advance. Love these forums.

Gabe - 1999 Hunter Passage 420

 

[Calif. Ted]

I've been having some battery issues (not charging at idle) that led me down this rabbit hole.

Most alternators have a "trigger" speed, they don't kick in until a certain RPM is reached (~2000 rpm) so if you just start and run at idle it won't charge until you hit the trigger speed.
Usually when a turbo engine is shut down the turbo can be heard to "spin down", wild ass guess on my part would be the turbo bearing .

 

[gsg900]

Thanks for the quick response.

It is a 63 Hp turbocharged diesel. So that makes sense in terms of the "spin down".

Looking at the manual it does seem to be serviceable without a haul - time to pull it and to find a good shop for a rebuild - or find a good mechanic who would stop by the boat...

And in terms of idle, my complaint with this boat is there is only one "power" lever so to raise idle I'd need to be in gear. I'll dig in to the charging issue more as it's now becoming clear I'll be at the docks for a few days.

Thanks again - and anyone else who wants to chime in is welcome. Great discussions (and resources) here.

 

[twalker H260]

You should be able to unlink the throttle from the shifter for cold starts/charging etc. Possibly a push button in the Center of the throttle pivot?

not sure if this is the same as yours.

https://forums.sailboatowners.com/attachments/lewmar-shifter-manual-pdf.129538/

 

[sailor420]

Our 2000 420 has a single shift/acceleration lever and there is a button at the pivot point that allows you to disengage the transmission by pushing it in and then when you return to neutral/idle setting it reset and will engage the trans

 

[Skipper Chris]

It sounds like you certainly have a bearing still in play after the shutdown. As has been mentioned possibly the turbo. Easy enough to check by any competent heavy equipment mechanic. And as you have learned, just push in that big black button in the center of your lever to disengage the drive and rev the engine.

Best of luck

 

[shemandr]

I don't know about engines but kudos for including a video with your question. There can be no doubt about what what the symptom is. With the little knowledge I have I would look at the turbo since the engine rotation has stopped when the whine begins. Or maybe we just can't hear it while the engine is rotating. Turbo diesels make a whining sound even if they are running normally. I know this from the Viking Montauk-Block Island "Fast" Ferry.

 

[gsg900]

Thanks all for that super neat trick to disengage the transmission. And here I thought that black end of the lever was just a nice decorative adornment. I never had the need to use anything but forward and reverse as I've always used the Gen when on the hook.

Went down this morning pushed in the button on the shift lever and voila I am running at 2k without running IN to things. Hadn't dug that deep into that section of manual, so again thanks.

SO - plot thickens (but work obviously remains):

I do have a charging (alternator) issue that I will dig deeper into. House batteries are not charging off the engine at any level (including 2000rpms). Charging fine on shore power and/or Gen.

AND - the turbo whine disappeared at shutdown once the engine was warm. Not that it doesn't bear continued investigating... just interesting. The video I attached before was a cold start and low idle of 3-5min max.

Now to find a good mechanic in the NY/CT area...

Oh and I know all about that "fast" ferry from Montauk to Block. See it in the GSP all the time.

Thanks again - always enjoyed these forums and appreciate the advice and consultation.

 

[flightlead404]

Are you sure your alternator is turning? Is the squeal coming from the alternator? Maybe that's the culprit since you're having charging issues.

 

[MikeHoncho]

That doesn’t sound like a high rpm squeal that would come from a turbo charger. Does it take place after the engine is no longer rotating? If not then I’d say it’s a alternator (fits the scenario the best) water pump or raw water pump bearings/bushing. I wouldn’t bother with any of it until you change out the alt and see how it spins by hand.