outdrive noise

[sinful]

i have a clicking noise coming from the rear of my engine it seems from where engine and outdrive meet.it seems only at idle if i rev the engine a little say to 1200 rpm it quiets down.the clicking is erratic,no pattern to it it may stop for a few seconds.this is a 87 mercruiser 260 with an alpha one.i had the lower gearset replaced by a respectable marine service last year,but it was only warranteed for i calender year which is up.the clicking to me sounds like something light,not a real clunk has anyone had a problem resembling this any help will be appreciated

 

[WillyBWright]

Re: outdrive noise

First thing you'll want to check is the prop. Make sure the prop nut is tight. If that's loose, the sound can track thru the drivetrain and eminate from elsewhere.

 

[rabidfish]

Re: outdrive noise

It's probably the exhaust "flappers". they act as one way check valves to prevent water reversion into the engine.<br /><br />They start out coated with rubber, but the rubber gets melted off with a lack of water overheat, then the exposed metal "taps" on the aluminum exhaust pipe. <br /><br />You can probably use the boat until the parts come in. I wouldn't go very long though. If those things fall out, they could wear a hole in the bottom of the "Y" pipe. (read: direct hole to the lake!)

 

[Don S]

Re: outdrive noise

I'd second the exhaust shutters. They are very easy to change, and if you remove the riser, it gives you a chance to inspect the condition of the riser and manifold water passages.<br />Those shutters are #6 in the picture.<br /><br />