How do I improve gas mileage on my boat motor?

Discussion in 'Boat Tips' started by Aftercats, Aug 10, 2006.

  1. Aftercats

    Aftercats New Member

    Messages:
    236
    State:
    Tennesse
    I just got back from overseas and retired from the Army. When I got my boat back from my Father's in California. He had it tuned up for me out there and sent it to me here in Tennessee. It really seems like it is sucking gas down to quickly. It is an Evinrude 88 horse, two stroke. Someone told me I might have to do the tune up over as it may be set to California's emision standards. Any help would be greatly appricated. Thank you

    Daryl
    Aftercats
     
  2. Norm

    Norm New Member

    Messages:
    65
    State:
    Freeport, IL
    Rowing or drifting will increase gas mileage alot.
     

  3. IL_CATFISH

    IL_CATFISH New Member

    Messages:
    248
    State:
    Illinois
    As would a smaller motor.

    I'm tellin ya, that 'liquid gold' is a killer!
     
  4. ncfowler

    ncfowler Well-Known Member

    Messages:
    2,695
    State:
    NC
    Name:
    Jeff
    first i would taken your buds advise and have a local marina check out that your have a good carb mix for your area,
    if your prop pitch is too low it will give you a good hole shot but low top end and your motor will run a higher rpm causing excess full comsumpton :
    for exalmple I have a 18' center consol with a 75 hp running a 17" pitch it gives me a good hole shot and great speed but at high speed i can get cavation and loose speed, a 19"pitch gives me less cavation but my hole shot is fair but i lose some of my trim , What I trying to say is changing prop pitch may be some help, also play around with your trim I will usualy trim out as i get up to speed to maximise and get that extra mph but too much trim may end up a bad thing as well causing purposing or plowing. also using a higer octaine will give some more kick like a car using a higer octaine gives better gas mileage. also weight distubution in the boat is a major factror getting even weight will help. I do alot of duck hunting "Lots of equipment" getting the weight evenly distrubuted helps alot. and if all else fails get a 4 stoke or the new etec form evenrude
     
  5. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Only use the octane specified for the motor. Most engines today are run on 87 octane. I have an 80's model mariner that specifies 93.
    I'll always do what the book says when 60 horses will cost 5000 or more.

    If you want better fuel mileage short of buying a new motor, put a Doel Fin on the motor. You'll see a mileage increase of 20-50%. I almost doubled mine with one simply because I could keep the boat on plane at lower speeds and I could jump on plane real quick.
    They are a real advantage on bass boat hulls as they are not effecient hulls at low speed.
     
  6. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    It is probably not using any more gas than it did when you last operated it. It is just that with gas over $3.00 a gallon, everybody is concerned as to how fast it is consumed. I think you bite the bullet right now while your learning the lake/river your fishing. Once you learn it, you can anchor or drift and cut the consumption way down.

    Also, use a good grade marine wax on the bottom/side of the hull. Get the scum off and a nice coat of polish on. That helps a lot.

    Now that your retired, welcome to the world of small paychecks. LOL
     
  7. SilverCross

    SilverCross New Member

    Messages:
    1,562
    State:
    Fairbury, Illin
    Welcome to the BOC, can't help you on the motor though.
     
  8. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Daryl lets start with first things first. Do a compression check and post back the numbers. Now tell me what plugs you have in it and what year it is. I think That 88 was a V and if I am right here it is a gas consumer but can be tuned to run efficiently.

    An I would say it has been tuned to Calif. specs and it will use more fuel here.

    I also want you to tell me what kind of boat you have it on and walk around back let the motor down all the way and take a picture of the lower unit. I want to see where the anticavation plate is located in correlation with the keel.
     
  9. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    Lawrence, race/drag boats I've seen don't have shiny bottoms. Helps to eliminate the vacume effect.
     
  10. duxsrus

    duxsrus New Member

    Messages:
    1,014
    State:
    SW Ohio
    I don't know if it's possible in your application or not, but removing some weight might help. Only take with you what you absolutely need.
     
  11. samh

    samh New Member

    Messages:
    807
    State:
    Damascus,Arkansas
    cut the RPM's back, my Merc 150 will get almost double the mileage at 4000RPM compared to 5000.
     
  12. Aftercats

    Aftercats New Member

    Messages:
    236
    State:
    Tennesse
    I have a 1989 17' 8" Alumacraft with 1989 88hp Evinrude the boat modified V hull bass boat I will post some pictures in the morning and I certainly appricate your help!

    Daryl
    Aftercats
     
  13. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    BobPaul - I don't want to hijack the thread, but can you expand on this "vacuum" effect? I never heard of it.
     
  14. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    When you have two wet surfaces come in contact together and both are slick and also wet it will creat a vacume between the to slick surfaces when you try to move one away from the other. small effect but will hinder moving objects none the less.
     
  15. TxRiverman

    TxRiverman New Member

    Messages:
    324
    State:
    Lockhart Tx
    Break out the oars:lol: !
     
  16. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    Another example is to put two mirrors face to face and try to pull them apart
     
  17. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    Back to the mileage subject;

    I've been water testing a 20' wellcraft with a carburated 200Johnson on it. It's been a problem getting it to come up to speed without hesitation or rough spots in the excelloration.

    Top rpms have only been 4800 rpm's with a 21 pitch prop, and extreme gas consumption.

    Dropped the prop down to a 19 pitch and lost some hesitation and top rpm's almost hit 6000. The boat was faster, the engine ran easier, less load on it,and best of all we didn't use near the gas as the first to runs. It was easy to see the gas consumtion because we were using a 6 gallon shop tank.

    I've still got a little fine tuning to do, but that slug of a boat will now roll your butt out the back if your not holding on.
     
  18. joesf

    joesf New Member

    Messages:
    283
    State:
    Bloomington IL
    So should we all take ballpien hammers and dimple our hulls like golfballs or what?
     
  19. Aftercats

    Aftercats New Member

    Messages:
    236
    State:
    Tennesse
    Here is the first 3 shots:
    ENG RH.jpg
    ENG RS.jpg
    RHS ENG.jpg

    Sorry I don't know my left from my right these days.....HA.
     
  20. Aftercats

    Aftercats New Member

    Messages:
    236
    State:
    Tennesse