1987 Mariner 90hp

Discussion in 'Bubba's Outboards' started by loanwizard, Mar 31, 2006.

  1. loanwizard

    loanwizard Well-Known Member

    Messages:
    3,297
    State:
    Coshocton,
    I just bought a 28 foot pontoon with a 90 hp Mariner and have a couple of questions.

    1. What is the oil to gas ratio 25:1 50:1 or 100:1?


    2. How difficult is it to replace a water pump and how often should I do it?


    3. Any ideas how fast this should push her? It started fine with the muffs and shifts well, but I don't need to have unnecessary difficulty on the water.


    4. What kind of fuel consumption should I expect? I've had a lot of small motors that I never had that worry, and my 225 Johnson eats it. I only have 2 6 gallon tanks aboard. Should I haul another along or is this sufficient when out playing with the kids? (tubes and traveling)



    5. Is it ok to use a deep cell battery as the main battery? It has the screw top which it how this motor is set up as compared to a regular side post or top post battery.

    Many thanks in advance.

    Shawn
    www.coshoctoncars.com
     
  2. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill

    Fuel Ratio will be 50:1 mix with a 87 octane or better gas. Never run a motor at 100:1 any motor made from 1964 on uses 50:1 mix

    Changing the pump or just the impeller is pretty straight forward.
    You should get a Manuel to help with these things and it will save you money at the repair shop later.
    I run a lot in dirty water so I change my impeller every other season and change the whole pump every 3rd season.

    now as how fast I couldn't even began to guess because I can't see how much she weighs and how the motor is set up.

    Find the proper RPM range for it and try to run it within that range.
    Bob has probably got a book that can tell that but I don't have one.

    as for fuel use I would take a tank and put two gals in and see how far she travels because that is gonna depend on how hard you push it how much wind and weight you have.
     

  3. jtrew

    jtrew New Member

    Messages:
    4,404
    State:
    Little Rock, AR
    A rule of thumb is 1 gallon of gas per every 10 horsepower at full throttle. So, 90hp would be 9 gph at full throttle. Of course, this is just a starting place for figuring how much gas you need. As time goes on, you will be able to refine that figure for your particular outboard.
     
  4. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    Bubba's right on with the fuel ratio.

    Replace the impellor yrly, and get the manual. They're easier to do than johnsons.

    How fast? About 32 mph, if your lucky, pontoon boats aren't made for speed, but that 90 will hold you more consistantly at any speed it can get up to. The harder you run a pontoon the more you can expect stress cracks in the bracing. get a motor support for trailering, if you do that.

    Fuel consumption will be poor, as that motor will be working hard constantly. They can't plane, contrary to what others may post. Trimming the motor only pushes the bow up and the stern down, getting those wings on the front of your pontoons, slightly higher for less resistance, and you'll gain, slightly more speed. If you want to play all day, get two 12 gallon tanks.

    Get a cranking battery, designed for starting an engine, and not a duel purpose one. If what your describing is a deep cycle, they're not designed to take a constant charge. Save it for the accessory battery.

    I think after rereading your description, your talking about a battery with threaded posts, and has wing nuts on them. If that's what your talking about, they're fine as long as it's a cranking battery. Check the age of the battery.
     
  5. loanwizard

    loanwizard Well-Known Member

    Messages:
    3,297
    State:
    Coshocton,
    Thanks for the help fellas, how about the battery?

    Deep cell OK as starting battery for this motor?
     
  6. loanwizard

    loanwizard Well-Known Member

    Messages:
    3,297
    State:
    Coshocton,
    Thanks guys for the answers and yes Bobpaul that one with the wingnuts is correct lol!
     
  7. loanwizard

    loanwizard Well-Known Member

    Messages:
    3,297
    State:
    Coshocton,
    It's an interstate megatron deep cycle with 550 cold cranking amps if that helps.
     
  8. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    Get a cranking battery, designed for starting an engine, and not a duel purpose one. If what your describing is a deep cycle, they're not designed to take a constant charge. Save it for the accessory battery.


    Where'd I see that above paragraph recently?:p