Manifold steam and loud clicking noise

[2000 Elisa's Ring SR 24]

After a 2 hour cruise and backing down to idle speed a clicking noise comes from the port engine. It is fairly loud after the hatch is open. After 20 - 25 seconds steam seems to come from the manifolds. Any suggestions on what to look at first?

 

[crazy charlie]

Re: Manifold steam and loud clicking noise

It is the exhaust flappers.Take a broom stick and place the end where you think the sound is coming from and then stick the other end in your ear.Now move the end of the stick onto the tube coming off of the back of the riser.Do you hear the flappers??? Charlie

 

[2000 Elisa's Ring SR 24]

Re: Manifold steam and loud clicking noise

I probably wasn't clear in my explanation, the noise is constant as soon as the engine is started, cold or hot. After 20 - 25 seconds the steam or smoke can be seen behind the manifold, the metallic clicking continues.<br /><br />The engines are merc 7.4L carb longblocks. The manifolds were replaced in July, could they need re-torquing?

 

[Scaaty]

Re: Manifold steam and loud clicking noise

Somethings cracked maybe. Pull a plug wire on a cylinder where it seems like its coming from (L/R side), and start it up. Keep doing it until you find the bad cylinder (sound will quit if its an exhaust manifold prob). Then take it from there.

 

[Haut Medoc]

Re: Manifold steam and loud clicking noise

It almost sounds like a hole in a piston from detonation......I'm not saying thats it....I am saying I would do a compression check though...A vacuum test could be real helpful, too....JK

 

[2000 Elisa's Ring SR 24]

Re: Manifold steam and loud clicking noise

If something was cracked wouldn't there be water in the oil or wouldn't the engine run hotter. Temp never changed in the engine, ran at a cool 160 degrees and oil is clean.

 

[Bondo]

Re: Manifold steam and loud clicking noise

It sounds to Me like the Flapper might have Broken,+ Caused a Hole in the Y pipe,........

 

[Haut Medoc]

Re: Manifold steam and loud clicking noise

I *** sumed that a thorough visual insppection had been performed.....By all means follow all of the previous posts to locate the source....JK

 

[2000 Elisa's Ring SR 24]

Re: Manifold steam and loud clicking noise

Service guy looked at it today, blew a manifold gasket because the bolts weren't tight. Still is a small antifreeze leak from the riser though.