Exhaust Pipe Clicking

[Dali007]

Hi all,
I have a Catalina 30 1980.

I had issues (up until now) where the engine would suddenly come to stop. We determined that it was a loose connector at the cockpit panel, after replacing many parts (the list is long and many hours of trial and error * pretty much everything was tested).

Now there is s constant and loud clicking noise "coming from inside of the exhaust pipe" located inside the port lazarette in the cockpit. I have owned the boat for 7 years, never replaced the pipe and the the noise was not present. This loud noise does not seem to interfere with proper engine operation.

Could someone shed some light with this issue?

Many thanks in advance, Dali

[ndutton]

You're hearing a swing check valve flapper banging against its seat.

[Dali007]

Thanks so much for your reply, someone at the club said the same thing.

Would you know why is this happening all of a sudden? And also, how do I repair this?

[ndutton]

Those check valves aren't known for their reliability particularly due to the steel hinge pin. I'm hesitant to recommend doing away with a factory feature designed to protect the engine from backflooding but . . . . . .

You can always replace it but there's no assurance the new one won't make the same noise. If you decide on replacement, McMaster-Carr has them in stainless (I think the factory original was bronze).

[ndutton]

Originally Posted by ndutton

You're hearing a swing check valve flapper banging against its seat.

This thread reminded me that I hadn't heard this noise in quite a while suggesting I'd fallen victim to the steel flapper pivot pin and possibly developed an exhaust restriction because of it. Two days ago I removed the assembly with the check valve, took it apart it and found the flapper in place, only stuck open. As discussed in the thread, a decision had to be made re: eliminating the valve altogether or replacement. I opted for replacement for two reasons:

• With the excellent winds in my area I often bury the port rail and in that attitude 99% of the exhaust system is below the waterline.
• The Catalina 30 has a marginal waterlift exhaust design in the first place so I'd prefer all the backflood prevention I can get.

Therefore a new stainless check valve is on order. As long as I'm working on the system, new exhaust hose is on order too. Caution: the great exhaust hose price offered by Overton's ($73 for 12½ feet) didn't look so good when they added $167 for freight in the fine print at checkout.

[hanleyclifford]

If ever there were a group of production boats that could benefit from a jacketed system, the Catalina 30 is it. Plenty of them out there and mostly well engineered except for that exhaust.

[ndutton]

My opinion is the Catalina design as installed at the factory is fine and nearly 8000 Catalina 30's bear this out. It's when owners who think they know more than the factory get involved and "improve" the design that problems result. Of course then it's a Catalina 30 with exhaust design problems and Catalina gets the blame.

I happen to think the Catalina 30 exhaust design is limited due to engine placement and cabinetry configuration therefore all the more reason to follow the factory example faithfully.

[hanleyclifford]

So I wonder what came first at Catalina - the limitations due to engine placement and cabinet configuration, or the admonition to limit attempts at improvement?