Ticking noise - 2006 SN196 PCM EX 330 (5.7l)

[mdleng]

I have a ticking noise that I believe started 80-90hrs ago after an oil change and is very slowly getting a bit noisier. Boat/motor has 370hrs on it (boat was rarely used before I bought it a year ago). I've done 3 oil changes now since purchasing the boat. I'm using the Rotella 15W-40 as recommended in the manual. The ticking correlates to the rpm and continues as RPM increases. While the ticking doesn't go away with higher RPM, it doesn't get louder with higher RPM, it's harder to distinguish from the other normal engine noise as RPM increases. It appears to be originating from the top of the motor in the area of the flame arrestor/coil/EFI tubes/distributor. I can't feel any perceptible vibration on any parts that correlate to the ticking. If I move down the sides of the engine the noise is not there. No other symptoms other than a very slight hesitation on the throttle when the engine is cold and I move from neutral to forward/reverse as I maneuver the boat out of the slip or off a trailer.

Any ideas? Ignore until something worse shows up?

[charlesml3]

First thing: Do not ignore it. Whatever it is, it won't get better, only worse.

It might be a leak in an exhaust riser gasket. I worked on a Excaliber once that had a bad "ticking" sound that was a riser gasket. Is the boat down on power at all?

-Charles

[swatguy]

I am far from an engine guru , but what you describe sounds like a leak in the exhaust manifold gasket. Usually that tic by the intake is correlated to that. Feel around the seals and I bet you’ll find your answer. The fact the boat sat for a bit makes that seem to be a reasonable inference as well. Those gasket/seals tend to deteriorate when not in use. You lose power ever so slightly when you have a leak there. As the boat warms up it’s the gasket tends to heat and expanded take up little of the void and not get louder. My guess with loss of power and tic , it’s an exhaust manifold gasket leak. Fairly common.

[SilentSeven]

Here's an old mechanics trick that might help. Get a ~ 2 to 3 ft piece of automotive heater hose. Hold one end to your ear and move the other end around the engine to help locate the noise. An exhaust leak is a good hypothesis. I was going to suggest a noisy fuel injector but I like the exhaust leak better.

[A_Connell]

Hi guys,

My boat has the exact same issue as OP. Can someone confirm if this fix actually solved the problem?

Thanks