Mercruiser 140 Exhaust Shutter?

[bjarnold1]

I have a 1984 Seaswirl 20ft with a 140 3.0 Mercruiser and today on the lake I noticed a noise only at idle. After getting home I started it on the hose and made sure there was no loose bolts or hardware (it sounds like something rattling around in the flywheel cover). I checked the exhaust flapper and it's in good shape except for the two mounts on the ends that have the rubber missing. Could this be the problem?

Thanks

 

[ziggy]

Re: Mercruiser 140 Exhaust Shutter?

I checked the exhaust flapper and it's in good shape except for the two mounts on the ends that have the rubber missing. Could this be the problem?

it could be. flappers have been known to rattle i think. don't know about yers. but my service manual says use some silicon sealer on the ends. i wondered why. perhaps its to keep it from rattleing.

since ya think the flappers are ok. the problem hasn't been located yet. i use a hearing hose to help locate noises. a hearing hose is any leangth heater hose or the likes. listen in the hose while searching for the noise with the other end.......

 

[Don S]

Re: Mercruiser 140 Exhaust Shutter?

I checked the exhaust flapper and it's in good shape except for the two mounts on the ends that have the rubber missing

Well, if the ends have the rubber missing, I would guess that means the flapper is NOT in good shape.
Do you know what a new one looks like? Did the old one have rubber around the edges (That isn't worn thru)

Might also have a look at the tin cover that goes under the engine and covers the flywheel opening behind the pan. The rattle if loose.