Prop Help

Discussion in 'Boating' started by Defiant, Mar 16, 2007.

  1. Defiant

    Defiant New Member

    Messages:
    76
    State:
    West Virginia
    Picked up another boat recently and need help with choosing a Prop. The motor is a 86 35 hp Mercury with a 13 Pitch prop the motor runs real strong but only gets up to 4800 RPMS and the motor is rated between 4500 and 5500 RPM so should I go to a 11p 10.5p or 10p prop to get it close to the limit ? Thanks
     
  2. on_the_fly

    on_the_fly New Member

    Messages:
    606
    State:
    Kentucky
    it would depend on what you want if your looking for speed or hole shot or the in between. myself I like both i could get about five to eight mph if I went with a sharper pitch but I like to jump and go too. with out having a 20 thou beefed up motor you will give up one for the other. mabey not enough you will care much, but you will loose one end for the other defanatly on a smaller motor. so getting full RPM might not be what you want.
     

  3. Defiant

    Defiant New Member

    Messages:
    76
    State:
    West Virginia
    Thanks for the reply Leroy . Somewhere close would be fine never messed with Merc's much so dont know what to expect from it .Like I said the motor is very strong and runs very well gets up to 24 MPH now with a medium load on the 16 ft boat it's on. The 11 might be close enough to just get the RPM up a little .
     
  4. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    For every number dropped you should gain about 150 to 200 rpm's If it were mine I would go with a 10.5 and have it cupped. That would give you good bite less slip and decent fuel useage.
     
  5. dougc

    dougc Active Member

    Messages:
    1,710
    State:
    Independen
    What's the ambient air temperature when you're testing the prop?
     
  6. Katmandeux

    Katmandeux New Member

    Messages:
    1,618
    State:
    Checotah, Oklahoma
    Go to this site, and do some reading...it will answer your question, and more.:smile2:

    http://www.miwheel.com/
     
  7. Ol Whiskers

    Ol Whiskers New Member

    Messages:
    290
    State:
    Fairfield Township, Ohio
  8. Defiant

    Defiant New Member

    Messages:
    76
    State:
    West Virginia
    Thanks everyone I have been looking at Michigan Wheel and some others the problem is that I called a few dealers and ask them and got different answers from them all .Some say dont go below a 12 others say go to a 10 :lol: But I have been thinking of the 10.5 like BubbaKat said just dont have any prop shops around here to do any adjusting or nothing so what I get I get.

    I want it do get my RPM's up but not loose to much topend also so maybe the 10.5 or 11 is the Ticket also would you all go stainless or stay with alum with this smaller motor? Thanks
     
  9. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    If you can't get a shop to cup that 10.5 then go with the 11 and make sure the anticavation plate is up even with the bottom of the keel or no higher then 1 inch above the keel.
    My self I would stick with alum. Because It is forgiving when it hits something. If you are running stainless , sure you will have better performance but you hit something and it just might take out the whole lower unit. Then you would be in a worse case then you already are.

    Take into consideration your main goal is to have a unit that will perform in a continuous trouble free fashion. When changing anything on an outboard you will affect something else. I don't mind sacrificing a little speed for good performance.

    If you keep running that motor at4800 rpm's you are lugging that motor and while you are running that prop you have I would keep plenty of seafoam in the fuel because without running at the recommended rpm's that engine is not burning all the fuel and it is coking inside the cylinders and eventually will break a ring or score a wall.
     
  10. Defiant

    Defiant New Member

    Messages:
    76
    State:
    West Virginia
    Thanks again BubbaKat around here there are no shops you have to send it away to get it worked on. The 11 should get me up to at least 5200-5300 with a medium load just hope it's ok with a heavy load. I decarbed the motor ,rebuilt carb ,and fuel pump although it ran good did find some bubbles on fuel pump diaphram also changed impeller, want it running good before the cats really start biting good .

    Also is there a prop you all reccommend over the others Michigan Wheel ,Solas ,Hustler or does it really matter Have been looking at the MW Vortex
     
  11. Defiant

    Defiant New Member

    Messages:
    76
    State:
    West Virginia