Blower or no blower?

Discussion in 'General Discussion' started by Groucho, Nov 7, 2019.

  1. Stee6043

    Stee6043 Well-Known Member

    Jun 1, 2015
    West Michigan
    1997 Sundancer 400
    7.4L Gassers
    I pretty much run mine non-stop unless I'm on a long trip on-plane. It's habit...
  2. Golfman25

    Golfman25 Well-Known Member

    Sep 12, 2009
    Years ago I read somewhere that you really didn't need to run the blower after you got going. Something about the amount of air the engines use is enough to evacuate the engine room. I usually forget to turn it off though.
  3. Great Lakes

    Great Lakes Well-Known Member GOLD Sponsor

    Oct 11, 2016
    Lake St. Clair - Michigan (MacRay Harbor)
    2005 390 Sundancer
    GHS Platform
    Bow/Stern Thrusters
    Same routine
  4. b_arrington

    b_arrington Well-Known Member GOLD Sponsor

    Feb 21, 2007
    Setauket, NY
    2018 Back Cove 34
    Cummins QSB 6.7 480
    When I had a gas boat my son had a like of duties when we boarded.
    1. Open the front windows (the boat was usually hot)
    2. Turn on the battery switches
    3. Turn on the blower
    I would leave it on until we were away from the dock. Turn on again before a restart.

    As far as fueling, I took the precautions very seriously. No one allowed in the boat while fueling, open and check spaces after fueling, run the blower before restart.

    Now that I have a diesel I use the blower to help cool the engine after running. The owners manual says to idle the engine in gear for a period of time after running, then run the blower for 20 minutes after shutdown. I have a fairly long no-wake period to my slip that takes care of the first part. I’ll usually hit the blower when I get to the start of the no wake zone and turn it off when I leave the boat.
  5. GypsmJim

    GypsmJim Active Member

    Aug 8, 2018
    Western New York
    '19 SPX 190 OB, 150 & 5 Mercs
    '17 Whaler 150 Montauk
    '15 Yamaha FXHO
    '60 Mulray Dinghy
    '52 Lyman 15'
    Mercury 150 4-stroke
    68 Outboards representing 11 manufacturers
    Anyone that doesn't use a blower should be required to take (or re-take) a boating safety course.
    villain style and Chris-380 like this.
  6. MonacoMike

    MonacoMike Well-Known Member

    Sep 15, 2009
    Indiana lakes and Lake Michigan
    2000 Cruisers 3870
    8.2 Mercs
    85 Sea Ray Monaco 197
    260hp Alpha 1
    This is my routine as well...

    markrsimon likes this.
  7. Ike

    Ike Active Member

    Dec 17, 2011
    Pacific Northwest
    1972 Sea Ray SRV 190 I/O
    12 Ft Rowboat
    8 Foot Sailing Dinghy
    Mercruiser 165 6cyl inline GM 250
    Blowers are not only an ABYC requirement, they are required by the Coast Guard on all boats with permanently installed gasoline engines. There should be a blower warning label on the dash saying to run your blower for 4 minutes before startup. I do the same as creekwood. I turn on the battery switch and turn on the blower. In my Coast Guard career I investigated far too many boat explosions to now say, "oh, I don't need to do that" .

    By the way, on the subject of diesels, Diesels need lots of air to breath properly. Boat manufacturers are notorious for not making the vents big enough to supply adequate amounts of air. Running the blower will certainly help by moving more air through the engine compartment.
    Chris-380 likes this.
  8. Groucho

    Groucho Well-Known Member

    Jun 11, 2008
    Albany/Lake George NY
    2004 320 DA
    6.2 V-Drives
  9. JimT

    JimT Well-Known Member GOLD Sponsor

    Jul 7, 2009
    Charlotte, NC- LKN
    2010 330 Sundancer
    T-350mags w/BIIIs & Axius, 5.0 kw Kohler
    They are so quiet you can barely hear them running.
    Groucho likes this.
  10. endless seas

    endless seas Well-Known Member SILVER Sponsor

    Feb 13, 2008
    1997 450 DA
    Cat 420
    Always let ours run...also to evacuate heat in the engine room.
    JVM225 likes this.
  11. JVM225

    JVM225 Well-Known Member GOLD Sponsor

    Apr 8, 2008
    Farmingdale, NY
    2002 410 Sundancer, Monaco Edition.
    3126 Cats.
    That’s why mine are always running. The diesels like all the air they can get.
  12. Coz

    Coz Member

    Oct 9, 2018
    2008 Sundancer 310
    Merc Mag 350 DTS w/Bravo III
    Which jabsco blower do you have? The 35770-0092 takes 11A. The stock 310da blower only uses 4A. Running both blowers on genny would cost you 22A. That would make the stock 30A battery charger pretty much worthless
    Last edited: Nov 9, 2019
  13. JimT

    JimT Well-Known Member GOLD Sponsor

    Jul 7, 2009
    Charlotte, NC- LKN
    2010 330 Sundancer
    T-350mags w/BIIIs & Axius, 5.0 kw Kohler
    I have the 35770 blowers. Never had a problem with the batteries.
    Chris-380 likes this.
  14. 370Dancer

    370Dancer Well-Known Member

    Oct 2, 2006
    Florida - Alabama
    1998 370 Sundancer
    380hp MAG MPI Gen VI with V drives
    Blower, Genset, Engines. Go somewhere. Engines, Genset, Blower. About 30 minutes after a serious run.
    Diesel or Gas. Same plan for different reasons.
    Chris-380 likes this.
  15. mobocracy

    mobocracy Active Member

    Jun 29, 2014
    United States
    310 Sundancer
    350 Mag & Bravo III
    I don't know about need, but there is a point at which engine aspiration exceeds the blower air movement. By my math, if you had twin 350s, it takes 2468 RPM to get 500 cfm of airflow.

    There's other questions, though, like the placement of blowers relative to the engine air intake -- they may venting air otherwise poorly circulated by engine air intake.

    I have no blower gripes other than they seem louder than my unshielded generator.
  16. Korkie

    Korkie Active Member GOLD Sponsor

    Feb 2, 2016
    Leonardtown, MD Potomac River / Chesapeake Bay
    340 Sundancer 2006, Garmin 7612, xHD Radome
    Merc 496 Mags
    Bravo III Drives
    Blowers on for at least 4 minutes prior to start. Get turned on while we are securing shore connections and doing pre start checks. Off back at pier after securing all lines, shore connections and helm. On while engines are running as well. Also have fume detector.
    Witnessed a boat go boom after poor practice while fueling. Only myself or my brother in law fuel our boats as we have the same procedure. Engines and electronics turned of and Everybody off the boat while fueling.
  17. BillK2632

    BillK2632 Well-Known Member GOLD Sponsor

    Jun 25, 2009
    Lake Norman, NC
    1999 185 Bowrider,
    Mercruiser 4.3, Alpha I
    I run mine, before starting and when off plane - I usually have opened the engine hatch if it's the beginning of the day or if I have just fueled - I still like the sniff test. Yeas ago I saw a Correct Craft Mustang blow up after fueling, don't know what happened, but it burnt to the water line pretty quick - luckily the two fellas in it were ok. That was in the days when people sat on the gunnel of those old ski boats, it blew both of them in the water away from the boat. Gasoline is just scary, in liquid form it's pretty harmless, but add some fumes and you have a bomb!
  18. hottoddie

    hottoddie Well-Known Member

    Jan 11, 2012
    Boston/Cape Cod
    1986 Sea Ray 390 EC
    Garmin 4212 Chartplotter
    Garmin 24 HD Radar
    Garmin 546s Plotter
    454 Crusaders
    Not sure why anyone would not run the blower 100% of the time the main engines are running. What harm can it do. They don't draw enough current to drain the batteries and can only benefit they bilge by circulating fresh air and helping the bilge stay a little cooler. I run mine 100% of the time while the main engines are running as the starboard blower intakes air and the port blower exhausts air, that's how Sea Ray wired the boat and I think it makes sense. Other boats may be wired differently for different reasons but as a rule I would suggest running them 100% of the time.
    Chris-380 likes this.
  19. Thornton69

    Thornton69 Active Member

    Sep 15, 2014
    Northern BC
    1981 245 SDC
    1984 18' Valco sled
    5.7 260 Merc/ Bravo 2
    Evanrude 115/80 jet
    Have my doubts that the blowers even keep up to the volume of air engines require while cruising on step. Am sure they won't have much if anything for a load on an electrical system even if they do keep up. Also would guess they are probably spinning pretty good even while powered off under those conditions in the event that bearing life is of concern for not using them all the time. I do shut mine off on step when I think about it and am just thinking out loud.
  20. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    I don't run blowers, there're competing with the engines for fresh air. Your intake ducts will have to be large enough to supply fresh air to the engines and the blower. Engines will suck in plenty of fresh air own their own.

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