383 Rattling noise help

[pennyduke]

I had this same noise with my Mercruiser 5.0L. This is the new 383 during break in. I hear the same rattling noise. THE OUTDRIVE IS NOT ATTACHED. Any thoughts?

 

[NHGuy]

Exhaust flappers? If their silicone edges are burned off it's metal on metal.

 

[pennyduke]

Ok, Thanks for the reply. One side is new and I have a new one for the other side. Gonna try to put it in tonight. Thanks

 

[Bondo]

Ayuh,.... Who adjusted the valves,..?? Maybe a loose lifter,..??

The rpms seem to be to high for a shutter rattle,....

 

[pennyduke]

I adjusted the valves. It just seems like it may be the exhaust flap because the other motor made the exact same noise before it was pulled. I'm gonna replace that first then hope for the best. I will report back. Thanks

 

[pennyduke]

I replaced the port side exhaust shutter and the noise is completely gone now. The rubber coating was wore off on one side of the old one. Thanks all for the help!!!

 

[NHGuy]

Good, I'm glad it was not your motor!