When to use Bilge Blower/When Not to use Bilge Blower

TimB19

Cadet
Joined
Feb 13, 2019
Messages
13
Our family has a boat we use every year up on the Lake and for many years we have had an I/O boat so I had to get used to the concept of when to use the Bilge Blower. What is the reason to cut the bilge blower off when above plane/at cruising speed?
We have a Stingray Bowrider and it has no forward facing slots like older boats, thinking 50's Century, where air can enter into and exit. I'm guessing the air collects at the bottom portion of the boat and I know there are side slots on most I/O boats on the interior sides where drink holders are that are open back to the engine compartment...do they catch the airflow? Or does the air filter simply suck enough of the engine compartment fumes out of the bay.....I read running the blower would fight against this at cruising speed?
As it stands I run the blower 1min before starting, smell the output for any strong fumes, and if clear start up, and continue running under cruise or when in no wake zones. I also like to run it while docking after a ride.
Some people say they leave it on all the time, which I think would greatly lower the units life and drain the battery.
 

harringtondav

Commander
Joined
May 26, 2018
Messages
2,438
My theory: Once underway on a plane the bilge self vents. My boat has two vents on the upper transom. One side is piped to the bilge blower inlet. The other is open. I'm guessing there is lower air pressure behind a moving boat which drafts out the bilge. My boat has open passages from the cockpit into the engine bay to provide air for the carb, and extra to support engine bay venting.

There is no downside to keeping the blower running while the boat is running, except the blower will fail sooner. Inexpensive to replace. I shut mine off because the noise bugs me. But the charging system doesn't know it's even there. It's probably safer to keep the blower running. Once I vent the bilge for the first start, I tend to forget about it on subsequent start ups.

I've read posts here about the pros and cons of running the blower during refueling. No consensus.
 
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racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,033
Run blower per your manual.----5 minutes I think.-------I have seen a small boat go ---POOFFF---after refueling in a marina.-----It causes instant pandemonium I tell ya.-------So follow instructions or invest in parachutes for the family.-----Gasoline is not a joke.
 

DouglasW

Petty Officer 1st Class
Joined
Apr 20, 2018
Messages
269
I can't hear the vent motor well once the engine is running, so I usually forget to switch it off. Then when I do eventually go to idle later, I wonder what that strange noise is and worry it's something bad. For your sanity, try to switch it off ;-)
 

tpenfield

Moderator
Staff member
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Jul 18, 2011
Messages
17,620
I run the blower the prescribed 4 minutes before starting the engine and keep it on until I shut down the engine. It can’t hurt keeping it running while underway.
 

mickyryan

Rear Admiral
Joined
Apr 18, 2016
Messages
4,210
yeah i never shut a blower off , if its too loud upgrade it to a quieter one :) or sometimes just insulating it since they are just plastic bodies
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
Messages
47,297
undo the trailer tie-downs, turn on blower, back boat in water, tie off to dock, park truck, get back to boat, fire up the motor.....go boating.....come back to dock, tied off to dock, turn off motor, turn off blower, get truck, back in water, walk boat up trailer, pull boat, attach tie-downs, go home
 

TimB19

Cadet
Joined
Feb 13, 2019
Messages
13
Thx for the responses. I might just end up running the blower entire time for peace of mind.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,802
A few points no one mentioned:
1) always check for fumes before turning on the blower, if you smell gas you are not running the boat that day! This means lifting the engine hatch and using your nose. You can smell fuel at a much lower concentration than the gas fume detectors will alarm at. However, I rarely if ever see people do this at the gas dock. The ignorance of most boaters of the danger is frightening.
2) install a gas fume vapor detector, it should be standard equipment on gas powered inboards. I have one, very easy install and if a leak develops under way it will alert you to it. Otherwise you'd never know till its too late.
3) running the blower the whole time you are running the boat is probably safer, they do make blowers rated for continuous duty, one is the Yellowtail. I've had a total of 3 blowers on this boat over 17 years of ownership....
4) one time NOT to run it is when refueling. In some configurations it is possible for gas fumes to be drawn in the fresh air intake depending on how the boat and fuel fill is set up. On my boat the blower and exhaust vent are on the port side, the fuel fill and fresh air intake are on the starboard side. So if you ran the blower, it is possible for fumes to be drawn in. Most boating safety guides say to close all hatches and shut off all electrical when fueling.
 

DouglasW

Petty Officer 1st Class
Joined
Apr 20, 2018
Messages
269
A few points no one mentioned:
1) always check for fumes before turning on the blower, if you smell gas you are not running the boat that day! This means lifting the engine hatch and using your nose. You can smell fuel at a much lower concentration than the gas fume detectors will alarm at. However, I rarely if ever see people do this at the gas dock. The ignorance of most boaters of the danger is frightening.
2) install a gas fume vapor detector, it should be standard equipment on gas powered inboards. I have one, very easy install and if a leak develops under way it will alert you to it. Otherwise you'd never know till its too late.

1) I am that one guy that you rarely see lifting the engine cover to use the "human-powered" fume detector. I have gotten into the habit of always doing it.

2) Do you have a recommendation for a vapor detector?
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,802
You can get a simple Xintex Fireboy one that is easy to install....looks like they have gotten more complex and expensive since I installed one about 6 years ago....
 

DouglasW

Petty Officer 1st Class
Joined
Apr 20, 2018
Messages
269
You can get a simple Xintex Fireboy one that is easy to install....looks like they have gotten more complex and expensive since I installed one about 6 years ago....

Looks like I can buy one from Hodges with the blower interface for $148. Can you tell me if you tested it and the results? Thanks
 

Lou C

Supreme Mariner
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Nov 10, 2002
Messages
11,802
I have the simplest Xintex one that does not turn the blower. I did test the sensor with an open gas can and it takes a surprisingly high level of fumes to alarm it. The sensor had to be nearly in the neck of the open can to set it off. That’s why I said earlier your nose will detect far below the level that would cause an explosion.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,802
You can see it in this pic above the ignition switch. Fits in a standard size gauge opening.
 

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garbageguy

Lieutenant Commander
Joined
May 8, 2012
Messages
1,531
Suggest checking that your blower hose is not, is not easily, blocked. Some have been installed with a low point in them that can fill with water through vent openings from splashing or washing.
 

Mike63

Recruit
Joined
Dec 18, 2018
Messages
4
Am repowering boat , looking for the correct way bilge blower hoses are to be installed , mine are badly torn and just laying in the both sides of the engine in the bilge
 

mickyryan

Rear Admiral
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Apr 18, 2016
Messages
4,210
min. 24 inches apart and just above water getting into them in bilge area lowest part
 

mickyryan

Rear Admiral
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Apr 18, 2016
Messages
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I have the simplest Xintex one that does not turn the blower. I did test the sensor with an open gas can and it takes a surprisingly high level of fumes to alarm it. The sensor had to be nearly in the neck of the open can to set it off. That’s why I said earlier your nose will detect far below the level that would cause an explosion.

is exactly right , i used a sniffer on my boat to check for any leaks around the fittings and tank sadly sniffer went nuts next to poly tank on hi sensitivity lol but fittings were fine and i can still detect a faint gas od0r when its been shut for awhile so i installed a solar fan to keep that gone.
 

SkaterRace

Senior Chief Petty Officer
Joined
Mar 20, 2016
Messages
712
I get to the staging area and I turn it on, I then only turn it off after 5 minutes of running on plane. If I am putting along I will turn it on since you can't hear it over the engine.
 
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