Blower Hose Replacement

[Walleye Dan]

I replaced (or should say I installed) new blower hoses on my 89 Sunbird 4.3 OMC. Now, I've read some threads about proper routing but just want to make sure this is correct. I installed the hose to the pump from the bilge below the engine. This air is blowing from the blower out to a vent which now faces to the stern of the boat. (was facing toward the bow.) I installed a hose from the other side of the boat routed from the bilge below the engine to a vent which faces forward. (There was no hose on this one) But, there were two holes in both the port and starbord side collector boxes behind the vents. What would the second holes be for. I just covered them to force the air through the hoses. Any clues?

 

[NYBo]

Re: Blower Hose Replacement

The blower is sucking air out of the compartment, right?

The exhaust duct should be as low as possible but above the level of water that might collect in the bilge. A duct is not required nor desirable on the intake. I would remove that duct and open up that second hole on that air box to maximize flow.

 

[Walleye Dan]

Re: Blower Hose Replacement

The blower is sucking air out of the compartment, right?

The exhaust duct should be as low as possible but above the level of water that might collect in the bilge. A duct is not required nor desirable on the intake. I would remove that duct and open up that second hole on that air box to maximize flow.

good advice but it looks like no air from that vent would reach the engine compartment at all. It just flows to the inside port of the boat.

 

[NYBo]

Re: Blower Hose Replacement

I guess I'm not visualizing your setup properly. Can you post some pictures?

 

[smokeonthewater]

Re: Blower Hose Replacement

if the hose can reach the engine the so can the air... you do NOT want intake air ducted to the bilge... that spreads fumes and mixes them w oxygen... perfect recipe for explosion.

 

[Walleye Dan]

Re: Blower Hose Replacement

Thanks.....Makes total sense. Removing intake hose today! Reopening 2nd holes in both collection boxes. One more question....The vent that the blower hose goes to was turned toward the bow of the boat. I turned it to the rear. Should I put it back to facing front?

 

[smokeonthewater]

Re: Blower Hose Replacement

It's probably fine

 

[Outsider]

Re: Blower Hose Replacement

you do NOT want intake air ducted to the bilge... that spreads fumes and mixes them w oxygen... perfect recipe for explosion.

OK, so the blower sucks out the accumulated fumes from the bilge and leaves a vacuum? Intake air will flow to the bilge, regardless of source, by the same proportion it is being removed. Fresh air lowers the concentration of fumes and actually reduces the chance of explosion. My Albemarle has 4 hoses, two long and two short ( 1 each per side). One of the longs is attached to the blower and exhausts lower bilge air ...

 

[smokeonthewater]

Re: Blower Hose Replacement

and your point is.....


your intake air is ducted to the ENGINE ROOM... not the BILGE...... as air (with any fumes) is exhausted the intake air gently flows down to replace it... if it were ducted to the bilge it would come in at high velocity and spread the (heavier than air) fumes such that the exhaust could not effectively pick them up

 

[Outsider]

Re: Blower Hose Replacement

My engine is an I/O (as is the one being discussed) and immediately below the engine is the bilge, that's where the blower hose terminates. There is a longer 'inlet' hose down low on the opposite side, also, and two shorter hoses higher up (and the OP has louvers with four holes in the manifolds, hmmm). The engine manufacturer recommends running the blower before engine start and in idle ops. No super-sonic air induction to the 'engine room' (if you prefer), just clean air introduced throughout at the same rate air is exhausted. When running, there still is no super-sonic induction of air because the louvers are both pointed to the rear. Air is gently exchanged at the same rate it is removed because of differential pressure and access both high and low, no need for a typical fore-aft ram induction. The side ventilation louvers are both pointed to the rear because this boat is built for big water, orient one forward and there are many days when the 'engine room' would become a jacuzzi. The system has worked extremely well (and safely) for Albemarle for nearly four decades ... :facepalm:

There Are Some Absolutes In The Marine Industry, But This Ain't One Of 'Em.
​

 

[smokeonthewater]

Re: Blower Hose Replacement

You aren't understanding something here.... Intake hoses aren't a problem but intake should not be routed to the lower areas where the fumes collect...... Intake hoses are not needed unless the intake air must pass through another compartment. ........ ANY hose that is routed down to the lower area (bilge) IS or should be an EXHAUST hose...... An exhaust hose does NOT have to have a blower.....

Not all I/O's have intake vents on the outsize of the boat.... Many intake air from the passenger compartment and often without a louver.

The "longer 'inlet' hose" you mention is or should be an exhaust hose.... It is not forced via a blower but at speed it should be drawing air out of the bilge.