mercruiser 3.0 exhaust flapper

[Mustangman 52]

I have a couple questions here i have have a rattle i cant find even after a motor rebuild sounds like a loose lifter triple checked by 2 marine mechanics all seems ok first question.Is this where my shutters should be on top of this pipe?( image) my motor is in 77 Starcraft serial number 3245055 as close as i can see is a 68-72 140 hp 3.0 does anyone know the correct flapper for this?parts catalogs shows a extra pipe i am not seeing on mine?also if the pieces are still in my exhaust can this make a rattle that sounds like the top end? Can anyone help me out thank you

 

[stonyloam]

This should give you a pn. http://www.mercruiserparts.com/bam/subassembly/30889/1586/120 Probably has been superseded with the new style. Chances are the pieces are all the way down in the exhaust chamber of the outdrive, or are long gone. Probably not making your sound.

 

[Mustangman 52]

my serial number is lower then the ones in the link but it looks like my exhaust. any ideas what else could cause a rattle its quiet at idle and sounds ok out of the hole but rattles when I let off on the throttle and at plane or slow down.(sounds like rocker arm noise) assuming all is ok in the engine as it is new.the machine shop insists the rattle is elsewhere .any ideas would be greatly appreciated.i was kinda hoping to find worn flappers gone seems to rule out this being my noise. [h=3][/h]

 

[airshot]

Exhaust shutter should not be confused with a lifter, as they are in different areas. The shutter only makes noise when it is working, if it is burned thru it is gone and no noise will come from there. I have a 3.0 myself and my service manual shows only one configuration for the exhaust. Are you using an actual "mercruiser" parts locator or an aftermarket? Your pic has many parts missing so are they not there or removed for the pic?

 

[Mustangman 52]

No Title

the link you sent me shows one piece as mine looks .the image here is what confused me this is supposed to be 3.0 new style i guess?.the image i uploaded of mine the only thing i removed was the exhaust hose and elbow form the top.

 

[Mustangman 52]

Different styles?you say I am missing many parts?

 

[stonyloam]

Yeah different styles, you have the older style shutter with the riveted bracket. I believe the parts link above is yours. The one you show is post 1982 I think.

 

[Mustangman 52]

Thank you.yes mine is riveted on one side and has to small bolts on the other side looks from what i can tell must have been replaced at one time its not riveted on all 4 spots.have you ever replaced one is it difficult?

 

[stonyloam]

Not that type, but it should be pretty easy. If you can unscrew those two bolts and remove the bracket and hing pin, the new one should just drop in. If it has been superseded by the "new" style shutter, that looks like it just sits on top of the pipe. You have done the hard part already.

 

[Mustangman 52]

so you think the new style does not have to be riveted back in it just sits in the pipe after i remove the old bracket.that would be nice. Another issue resolved seems the rattle well never be found.your Absolutely correct lifter and flapper is far apart.local marina suspected this to be my rattle since the motor is rebuilt.The machine shop pulled the head back off once already a valve got stuck after only a few hours on the motor they drilled and tapped new studs while it was off to be sure the noise is not in the heads the motor sounds better but after $2300 dollars i expect it not to rattle.I am very frustrated the boat was at the shop most of the summer..some mechanics say it may be the nature of the motor don,t worry about it ugggg.Thank you for the help

 

[stonyloam]

IF they make a new style for your engin yeah it sits on top, if not you need the bracket.

 

[Alumarine]

You don't have to worry about the rivets.
As stonyloam said you only have to remove the 2 small bolts to replace the flapper. The rivets stay intact.