Stbd and port blowers

Liberty44140

I noticed that when I run the blower switch at the panel for my generator it only runs the starboard blower, not the port blower. Odd because the generator is on the port side. When I switch on the blower switch at the helm both sides blowers come on but the starboard output air is much stronger than the port. Does this make sense? Port seems to put out a fine amount of air bit half as strong as the starboard. 

MDboater

It makes sense that you should draw air into the engine compartment from a location farthest from the generator exhaust.  

Just a guess.... if the blower wiring from the generator switch was undersized then there would be a higher voltage drop to the blower (but this seems unlikely).  Perhaps there is a resistor in series in the generator supply line to intentionally reduce the blower speed and extend the blower life.  Adding the second supply in parallel (from the helm switch) would lower the voltage drop and increase the blower speed.  

redlightning

I just replaced all 3 of my blower motors.  I had two on the starboard side and one on the port side.  The two on the starboard side were configured as one push and one pull.  The one on the port side is a single and pulls air out.  Not sure if this was any help. 

Liberty44140

Thanks for the replies. Sounds like this is normal to have the generator blower on the opposite side of the boat so as to not suck in the exhaust from the genset. Makes perfect sense. Perhaps they put a faster blower on that side to make sure to get everything out of the entire bilge since you are only running one side. The port blower works fine, you can feel good air coming out, just much stronger on Stbd side which is opposite genny. I have found that when running both blowers I notice a gas exhaust smell in the cabin after running generator and I'm thinking this is because Of running the blowers on both sides and sucking in exhaust. The intake is literally just above the genset exhaust. Could be a very important lesson learned to only use generator blower when generator is running . Ironically my dock mates were just telling me how they shut blowers off after they start the genny or mains, i usually leave them running while running any engine but perhaps they are right. 

Dream_Inn

Liberty, you bring up another good question.  I too run my blower the entire time the genny is running (& yes, mine is just one side).  I run them for my engines while I'm at idle, but once on plane I turn them off.  I know others that do differently.  I'd be curious what others do on this forum.

LaRea

We've talked before about getting dry ice in a bucket of water, filling the bilge with water vapor, and running the blowers to see what they are actually doing.  @Liberty44140 - seems like you'd be a good candidate to try it.  

Liberty44140

If I come across some dry ice I'll give it a try! I just replaced my blower duct work and exterior vents a few weeks ago so I know that there are no issues with the ducts. I think for now I'm going to stick to just the genny blower when the genny is involved and I may start to not run blowers once the genny or engines are on. Of course if something ever died I'd need to re run blowers before I could re start. 

TonyWalker

I have seen dry ice for sale at Publix.

TonyWalker

I used to run the blowers while cruising.  But I got to thinking that the blowers take air out of the engine room and so do the engines.  So it seemed to me that in that circumstance they just fight with each other.

Michael T

Ran blowers when Genny was on and while idling, blowers were off while cruising, otherwise IMO too much competition for air.

LaRea

Most chain grocery stores carry dry ice.

Black_Diamond

Interesting. My 342 has 2 blowers, run as you noted with only gen switch on (1) or at the helm (both). Both my blowers are on the stb side. Always wondered about sucking in genny exhaust. 

Liberty44140

BD, do you have grills on the port side not connected to the blowers? 

Handymans342

Yes we do

Black_Diamond

Yes.