Name that tune!

What’s up guys, got a 1978 260 engine and pre alpha drive. Just the other day I noticed a ticking sound. This sound is coming from the back of the engine and is most noticeable at idle/ low rpm.

I’m suspecting exhaust shutters/ flappers (and of course I have the 3 piece Y pipe) but can’t seem to pin point it. I can feel the vibration through the Y pipe but is there a better way to determine if the shutters are the problem?

the sound does not run with the rpm and goes away at higher rpm. It’s not a lifter or a rod from what I can tell.

Please give this video video a listen and tell me what you think.

https://youtu.be/j7JvTqY7QnI

thanks!

Anyone?

I removed the outdrive and ran the boat. Sounds still there.

Ayuh,.... Burnt shutters is My guess,.....

If you removed the drive and thus eliminated gimbal bearing and ujoint noises , shutters and valve train noises are all I would suspect. Shutters are easy to check, as listed above would bet the rubber is burnt off them .

It's not an exhaust manifold leak is it? That can sometimes sound like a tick, tick, tick.