Exhaust noise - 2004 320SD

[Dalma]

Beatiful day yesterday took the boat for a ride...First stop, Gas dock and the attendant overfilled and fuel was spilling out of the vents:smt013. Thats what I get for taking a walk during fueling. Second stop...sandbar for some lunch, a couple of bevvies, and maybe a swim...on our way there engine overheat alarm on starboard engine,...picked up a bag :smt021. Still a tough day on the water beats a good day at the office:grin:.

Aside from that, this boat is new to me last august. I have noticed that when up on plane around 3500 - 4000rpms there is a loud vibration noise, I think its coming from the exhaust ports on either side of the boat. Is this normal? Could it be something else?

Thanks for the help...

Jay

 

[skolbe]

Vibration is usually from props and shafts not being right. If the boat is louder than normal - then the boat is not getting enough raw water. Otherwise something is loose. Maybe check hose clamps, fitting and mufflers that everything is snug.

 

[Dalma]

Vibration is usually from props and shafts not being right. If the boat is louder than normal - then the boat is not getting enough raw water. Otherwise something is loose. Maybe check hose clamps, fitting and mufflers that everything is snug.

Thanks for the quick response skolbe. I probably should have eloborated a little more. There isn't a vibration in the boat, runs really smooth. It just sounds like a very loud humming or fluttering noise and the closer I get to the exhaust ports the louder it is, it almost seems like the water coming from the exhaust is sputtering? The engines are running at normal temp, which should mean i'm getting enough raw water? Everything is tight. I was reading some older threds and similar boats have an engine hatch issue which when I raised it up a little didn't solve my problem. It could be that I'm used to I/O's...but I had to ask around.

 

[AAK]

As a precaution I would recommend replacing the raw water pump impellers if you can't verify or have service records showing them being replaced in the last two years. You are already on the second season of your ownership since you had it last August. I did a write up on your exact boat of how to replace them if you are up to it. The access is the real problem in changing them. You should also change the impeller in the generator which is a very easy job to do. It goes with out saying that you should also check the strainers to see if anythings in the strainer baskets. It's a real nice boat and I'm sure you will enjoy it this season.

 

[skolbe]

I recently dinged a prop - the boat made a funny noise. Had the props redone and it went away.

 

[Dalma]

Thanks for all the responses. I think I better have the techs look at it this week, just to be safe. I checked the strainers and all is clear, but better safe then sorry.

Cheers,

 

[trit21]

I had the same exact noise you are talking about and if you lower the hatch so it seals more it will do away. THe problem has to do with the slot in the top mount for the engine hatch lifts, it will vibrate real bad at cruise. If while running, open the transom door so the hatch will move, and lower it slightly until the noise is gone. 2 boats I know including mine had the same problem. Be careful not to lower it enough to break anything but they are a lot tougher than you think they would be.

 

[billnpat]

As a precaution I would recommend replacing the raw water pump impellers if you can't verify or have service records showing them being replaced in the last two years. You are already on the second season of your ownership since you had it last August. I did a write up on your exact boat of how to replace them if you are up to it. The access is the real problem in changing them. You should also change the impeller in the generator which is a very easy job to do. It goes with out saying that you should also check the strainers to see if anythings in the strainer baskets. It's a real nice boat and I'm sure you will enjoy it this season.

This is a very interesting thread..... excessive engine noise , slight vibration at 3500 to 4000 rpm's?? very common from what i read...

I'm going to try:

http://www.acoustiblok.com/marine.php

soon to dampen the noise and help with vibration knowing for sure nothing else is amiss, we'll see, anyway yesterday i re-sealed the engine hatch and already its improved the deadening noise,