weird sound

[blazer]

I have a 1986 Alpha One on a 3.0L engine. Have been noticing a pinging sound or metal clickity sound slightly above the sound of the engine when the sterndrive is in gear upon acceleration or deceleration. It sounds good when boat is at speed. When revving out of gear sounds great. Any ideas on what this could be if anything? Thanks

 

[Bondo]

Re: weird sound

Ayuh,....

It could be Burnt up Shutters....

 

[chiefalen]

Re: weird sound

Do you know the history of the boat?

When was things checked and replaced last?

Any other symptoms?

Without seeing or touching your boat hard to tell what it could be.

Could be the outdrive? See any holes in the rubber when you raise it all the way up?

Gimbal bearing maybe, you keeping it greased?

U joint?

If this were my boat over the winter i would pull the drive and inspect everything.

If it's running good now leave it alone.

Good luck!

 

[gamarines2]

Re: weird sound

my diagnosis, based on personal experience is exhaust shutters. When you are running above idle, they are wide open, when you decelerate, they shut down to prevent water from backing up into the exhaust. When you see a tractor trailer with verticle exhaust, they have a similar setup on the top......just so you have a visual to think about.

Most of the shutters are made of a composite metal with a rubberized coating......this coating wears down over time and becomes a metal-on-metal clanking, typically only at idle. This doesn't necessarily mean they aren't doing their job, but it is a good sign that it is time to replace them.....

 

[gcboat]

Re: weird sound

Take a read thru here :http://www.outdriveshop.com/shutters.html

 

[blazer]

Re: weird sound

When I first bought the boat in 07 (my first boat) I fried the impeller. I was told the shutters were probably fried too. I took off the exhaust pipe and saw only 1/2 of the shutter left which had worn down to metal. I removed it and saw no sign of the other piece. Is this piece making the rattling noise? How do I remove it? Thanks

 

[Uraijit]

Re: weird sound

Take a read thru here :http://www.outdriveshop.com/shutters.html

Thanks for that link. I just did some reading up, and I'm 1bout 95% sure I need new shutters as well. I was hearing the pinging sound but only at idle.

I was thinking I needed new ones anyway, but didn't associate the 'pinging' with them!

Of course, mine are the older style, so I guess I'll have to see if I can change them without pulling the engine. If I can't, I'll just have to live with the noise, until after the season is over.