Ticking noise from exhaust port that quiets when water starts discharging thru hull

[Caveman22]

My '99 310 dancer started exhibiting a "ticking" noise from the starboard engine (350 mag)after being started. This noise appeared to dissipate when the cooling water would start flowing out the above water line exhaust ports. (As Heard from the dock) While having the engine covers opened during winterizing and running the engines to get them up to temp for oil changes, etc. I noticed that the ticking didn't go away from the exhaust system heard from the engine compartment. Used a stethoscope of hose to try and narrow down the noise. Can't pinpoint it, although does seem to be coming through the exhaust hoses, mufflers, etc. Any ideas?

Thanks, Dave

 

[Pirate Lady]

Do you have outdrives? if yes, its the exhaust flappers. They are right after the rubber hose between manifold and down pipes.
Does the noise go away when running on plane?

 

[Caveman22]

I have vdrives. I can't hear it when running on plane. Something in one of the mufflers?

Thanks!!

 

[Pirate Lady]

Not familiar with v drive. Sure sounds like flappers. Once running, they stay open hence no noise.
See if someone with v drives knows or ask local mechanic.