motor size

Discussion in 'Boating' started by catoon, Sep 17, 2008.

  1. catoon

    catoon Board Clown!

    Messages:
    1,387
    State:
    whiteville
    i have a 16 foot by 48 fisher all aluminum with a 40 horse nissan me and my wife fishes out of it seems under powered runs 20 miles an hour not to good of gas milage either i have a fin on the motor. i went from the ramp at the damn belowe pickwick to the island before you get to savana and back up to the ramp and ran out of gas there i had a 6 gallon tank is this normal
     
  2. cantstopgrandma

    cantstopgrandma New Member

    Messages:
    955
    State:
    MD
    Something doesn't sound right to me. My flat bottom jon 1448 with a 25hp yamaha will run 20-22 at a fast cruise speed. Top speed is about 28-29. I can go for hours on less than 6 gallons of gas, and this is a 2-stroke engine. Is your boat really heavy? If its set up like a bass boat, it will be pretty heavy i would imagine (at least compared to other aluminum boats with just seats). Is it a V bottom? V's take more power to push thru the water cause they ride in the water farther, and not just on top. You may have the wrong prop pitch, or the carbs may need a good cleaning/adjusting.
     

  3. catoon

    catoon Board Clown!

    Messages:
    1,387
    State:
    whiteville
    it is a heavy boat bass made it got about 20 miles on a tank of gas
    6 gallons
     
  4. Katmandeux

    Katmandeux New Member

    Messages:
    1,618
    State:
    Checotah, Oklahoma
    That's the downside of making a jon into a bassboat. You're gonna pay for all of that weight.

    If you're running your engine at or near WOT (wide open throttle) it will, as you've discovered, go through a lot of gas. A well set up boat should cruise on plane at or near half throttle.

    I'd put the boat on a diet, and get rid of everything you don't need. One thing to look at closely would be under deck flotation foam. That stuff can absorb water over time and add a substantial amount of weight to a boat.
     
  5. Mo.Hick

    Mo.Hick Active Member

    Messages:
    1,531
    State:
    Madison Mo.
    I agree weight is an issue. But where is the boat trimed at (to high to low). What pitch prop do you have? Can you over rev it. Is so the pitch on the prop is to low. Can you run close to the max rpm. If not the pitch is to high and that will burn a ton of gas working the motor to hard. This is also with where you have the trim set on the motor. Is the motor running right. Does it need a tune up. Hope this helps. There is a lot of things to look at and check. What is the boat rated for on horse power?

    Tom
     
  6. catoon

    catoon Board Clown!

    Messages:
    1,387
    State:
    whiteville
    i will get more info tonight and let you know
     
  7. JAYNC

    JAYNC Active Member

    Messages:
    1,312
    State:
    Newport N.C.
    Weight is your biggest enemy on a boat. Having a really good horsepower to weight ratio will help out a lot. IMHO put the biggest engine on a boat that it is rated for. That way the engine wont work as hard, it will last a lot longer also. If your boat is rated for the engine you have then the only thing you can do is cut weight. I have a 75 on my boat and it can go 45mph wide open or 32mph at 4k rpm. At that cruising speed I can get around 8mpg but if I want to run wide open which is only 1500rpm more I will only get about 4mpg. It always helps to have that extra horsepower to save gas. Hope this helped some.
     
  8. catfish kenny

    catfish kenny New Member

    Messages:
    6,064
    State:
    Iowa
    I aint no rocket scientist but you got issues bro..Bigger motor more gass but 6 g's ought to feed her fer a minute,,...another thing to check is how yer motor is set on your transom if it aint right you will suffer alot of drag...plane is tough....distribution of weight is a factor too.....not just weight itself I learned this the hard way and it cost me some gas....If you dont know how the motor is pose to sit I will try to get some pics and explain the best I can...I dont understand it all thouroughly but I know the difference:wink
     
  9. JAYNC

    JAYNC Active Member

    Messages:
    1,312
    State:
    Newport N.C.
    Go ahead and put a 4 cylinder in a full size truck and see what burns more gas. I guarantee you it will be the 4 cyl and not the v8.
     
  10. catoon

    catoon Board Clown!

    Messages:
    1,387
    State:
    whiteville
    kenny i have a minkota electric tilt on the boat it sets my motor back about 4 inches i was thinking want the water catch the jack plate and cause some dragg my boat is pretty heavy i might move up to 60 horse thats what it is rated at
     
  11. peewee williams

    peewee williams New Member

    Messages:
    3,111
    State:
    Pembroke,Georgia
    I found that burning up to 3 times the normal gas was normal when winds,tides currents and waves were against you in many situations.Going out in dangerous abnormal conditions for rescue and such can take 10 times or even more fuel for the same distance traveled.

    Taking along 3 times the gas normally needed was standard procedure for my 55+ years of boating.Most of it was burnt towing the dough heads that did not!This all must be figured in when deciding if something is wrong.You need to check under ideal conditions.A slight breeze and ripple will often improve fuel economy on a flat bottom boat!You have a process of elimination thing here.I planed my boats off and then dropped back to 1/2-2/3 throttle according to conditions.I bought motors that I could do this with.I often fished conditions where I could run as fast with a 2-8 hp.kicker as I could with my main motor,BUT I was in boats that could handle it.

    Any device attached to the foot of your motor will increase drag and eat fuel IF everything else is right.They only improve it IF something is wrong.

    I ran a 25 Evinrude from 1971 to 1983 on a Sears 16 foot long,6 foot wide,4 foot wide bottom.2 foot side open,100 thousandth heavy duty John boat.I thought that I got a good m.p.g.

    The only way to correctly measure m.p.g. in a boat is with no wind and no current.The perfect conditions needed are often had to find!

    I wish you the best.

    I love you Brothers and Sisters.peewee