Blower question

[martynj19]

Hi all, I have recently purchased a 1900 SR3 4.3 carb and I am going over the boat for my own piece of mind (checking connections and general lookaround) I have tested the blower system and found hole at the back of the ducting where it leaves the fan unit , fixed this no problem. When I operate the blower out of the water , I find the exhausted air exiting the port side vent , but I have noticed that air is also coming out of the fresh air ducting next to the battery. Is this normal ? maybe back pressure ? Any help is appreciated.

Martyn

[mmwjr]

Typically the blower only has one output and draws from the lowest point in the bilge.

There is a fresh air intake that bring air into the engine compartment about the height of the engine mounts and is non powered.

[martynj19]

Hi Mike , that is correct as per my installation , I cannot see how the ducting is terminated in the port side vent area , I am presuming that they should be seperated , but a certain amount of air definately comes out of the unpowered duct when the blower is on. Is there a schematic that shows the detail I am after?

Thanks

Martyn

[mmwjr]

Here is a link with some generic diagrams.

boat blower ventilation systems

Ok that did not work.

[mmwjr]

Ok iPad is not letting me copy links of images.

Google boat engine ventalation systems.

[mmwjr]

Try this

Bilge Blower Hose Routing Question - The Hull Truth - Boating and Fishing Forum

[martynj19]

Hi Mike , much appreciated , I think it is as I have suspected in that the blower is pressurising the port vent box and excess exhausted air is making its way down the "fresh" air ductwork. I will look into modifying it as per the install drawings you linked. Or investigate the vent connections further.
Thanks again.
Martyn

[mmwjr]

A blower should always draw out of the engine compartment and only pull air in from a fresh supply to cross ventilate.