342 blower ductwork

Liberty44140

in the process of running new blower ducts. Project started with replacing just the vent grills but the ducts were so dried out and easy to tear that I bought 50' of 4" duct (marine grade intended for marine bilge blowers and vents) and am replacing all of them. I have two grills on each side of the boat and then the two vents in the middle of the engine room that go in to the rear storage. My question to 342 owners is on the port and starboard ductwork. I have a long duct going from a low point in the bilge, to the blower and then up to the vent grill, all good on exhaust. There is a second vent grill to let air in right next to the exhaust which has no duct at all, never did. This concerns me because it can let some rain water in and on to the generator top lid. Do you all have a return air duct going down or are they all ductless like mine?

Cableguy Greg

On my 280, I have an exhaust duct from below the engine, and a fresh air that follows the exhaust duct. I also have 3 vents that do not have any hose on them leading to the side of the boat. I also have 2 vents in my rear storage hatch. I know it's not a 342, but I hope it helps. 

Liberty44140

Thanks. It's my hoseless vents that are a concern as they let rain water on to the genny. I am going to put short hoses on them just to channel the rain water elsewhere 

zaverin1

On my 280 I actually had no hoses lol
I have 4 vents
1 is for exhaust which goes to the bottom of the bilge and other 3 are all hooked up and go down into the engine compartment but not bilge level low.

Liberty44140

Here is what I did. Channels water that comes in to the air intake vents to places other than the top of the genny and water heater. I realize it looks like the starboard drains on a battery but it doesn't. lots of air come out of the exhausts so this should work out well.  

DanD2

Mine is like that...top of genny and batteries get a little wet sometimes but it's never been an issue

Liberty44140

On my 2001 310 I had to replace the stator and rotor on the genny to the tune of $5k due to water intrusion so I will accept no water on the genny. That boats genny had no sound shield at all and I have one now so I'm sure it's ok but not willing to risk it. 

cls10105

@Liberty44140,was the 50’ way to much or do you recommend getting that much and was it hard job replacing the duct work. Was it hard to get to?

Liberty44140

It was too much. I did all of the ducts with this 50’ including the ducts for intake, the blower ducts and the two vent ducts on top of the engines going in to the rear storage. Can’t remember how much I had left, 10 or 15 feet, probably could get away with 30 feet as I used a generous amount. It wasn’t simple, took a few hours, but it wasn’t a total bear either. Reccomend replacing the blower vents at the same time as you will already be there and already have to remove them so might as well put new in. 

Here is what I used, best price I could find, about $30 delivered for 50’.

http://www.discountmarinesupplies.com/product.cgi?product=138431&group=112933

cls10105

Thats awesome. Thanks man! I love this place!!

LaRea

@Liberty44140 care to post a photo or two of the result?  I'm "this close" to making this a spring project.  

Liberty44140

Hey @LaRea the ones here are all that I have but I can take some in a few weeks, indoor storage re opens feb 2 so I’ll be back on the boat most weekends 

Black_Diamond

My 342 only had hoses on the ‘exhaust’ side, All the intake vents had none. Go figure. I ran duct from the (4) intake vents down into the bilge so now all the fresh air has to flow into the low areas. 

Biggest pain is getting the hose on those grills that go the vents on the gunnels. 

Liberty44140

Yep agree, was a pain to get the hoses on the vents, wear long sleeves to get your arms up there. Extra hose helped, I pulled the hose out the vent hole, attached the hose to the vent and then put the vent in. 

cls10105

I went ahead and ordered 50’. I am worried about fitting my big a$$ in there.

pistole

Liberty44140 said:

On my 2001 310 I had to replace the stator and rotor on the genny to the tune of $5k due to water intrusion so I will accept no water on the genny. That boats genny had no sound shield at all and I have one now so I'm sure it's ok but not willing to risk it. 

agree. Water from the intake vents drained directly onto my genset on the STB side. Caused terrible corrosion in the black control box and genset itself , the genset's engine was spared.

Ian

So what is the correct setup for a 310, 2003 era?