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Thread: Fitting low water pick up to outboard engine

  1. #21
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    Seen this happen a few times since I started work on outboards, (1973). the failures usually don't care if they are OEM or Aftermarket. I have Used Both & have no opinion as to which is better now. Just nees to be sure that impeler is lubed liberally at installation & to minimize the dry " engine starts & simple spinovers". QC is just not what it used to be.

    Lawrence Thornton
    South Carolina Mellon Belly Associate.

  2. #22
    BRF Team Europe Member Per's Avatar
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    Quote Originally Posted by phillnjack View Post
    sharpeye mike
    ive just re-read your statement above about how you run your engine.
    you say its 15 inch midsection on a 21.5 transom and you get plenty of water ???????
    thats 6.5 inches up...you must be using a setback of some sort.
    if you bolt the engine direct to the boat at 6.5 inches up the transom, then on plane you shouldnt get enough
    water up that high to cool the engine, and with the longer sharper bullet it should be riding with bullet above the water.

    i cannot see how your getting anything over the water intakes at all without a setback..



    phill

    There are several interesting movies on youtube showing surfaced gercases, you will be surprised how high the water "climbs" or get pushed up. Normally you see a lot of spray comming from beneth the Anti ventilation plate, a good sign that the water has climbed past the std water inlet. Some people plug the upper intake holes that might be a good idea...

  3. #23
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    Attachment 51902

    Not sure if this work but if this pic. comes out you will be able to see how high we run these motors with no water issues and yes I block off the tree top holes and I drill out the tiny drain hole. I gained 3 lbs. of water pressure with this mod.
    Mike

  4. #24
    phillnjack
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    hold on a moment
    the centre of bullet is 2 inch below the bottom of the boat, yeah i get that bit.
    Now my gearcase is 4 inch and bit, so if i ran with the centre of bullet 2 inch below then the top of
    the bullet would be level with the water when on plane.
    Now the lowest hole on my engine is around 3.5 inch above the centre of bullet.

    in the pic below i have put a red line on the centre of the bullet.
    the yellow line is what sharpeye mike must have as a minimum water line.
    the green line is roughly where my water line is when on full throttle with the engine raised up to
    top bolt hole at the moment.

    this is why i am saying there is no way i can raise 5 inches and still get water, it would be impossible without the
    engine going back a long way.
    At full throttle about the last foot of the boat is all thats in the water and its very skittish and light on the arse end
    when trying to keep it in a straight line..
    .
    Name:  gearbox water line.jpg
Views: 4522
Size:  174.5 KB


    phill

  5. #25
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    Quote Originally Posted by phillnjack View Post
    hold on a moment
    the centre of bullet is 2 inch below the bottom of the boat, yeah i get that bit.
    Now my gearcase is 4 inch and bit, so if i ran with the centre of bullet 2 inch below then the top of
    the bullet would be level with the water when on plane.
    Now the lowest hole on my engine is around 3.5 inch above the centre of bullet.

    in the pic below i have put a red line on the centre of the bullet.
    the yellow line is what sharpeye mike must have as a minimum water line.
    the green line is roughly where my water line is when on full throttle with the engine raised up to
    top bolt hole at the moment.

    this is why i am saying there is no way i can raise 5 inches and still get water, it would be impossible without the
    engine going back a long way.
    At full throttle about the last foot of the boat is all thats in the water and its very skittish and light on the arse end
    when trying to keep it in a straight line..
    .
    Name:  gearbox water line.jpg
Views: 4522
Size:  174.5 KB


    phill
    In the picture my water line is about where the yellow line is or I should say the bottom of the boat is where the yellow line is, now I'm running a hi-jacker jack plate with 6 inches of setback. I've got my motor jacked up all the way and I think I may have to drill some holes in the jack plate to go up a spec higher. I had to have some cup added to the prop so it wouldn't cavitate so bad. I've run it raised all the way up but winter hit here and it's to cold to try the boat out with cup being added and the motor raised all the way up. I can say with no cup added and motor raised all the way up using a water pressure gauge the gauge would fluctuate a little but once on a plane it would have dam good water pressure.

    Still testing and would love to get back out there but gotta wait for it to warm up. I was actually able to see what the water is doing as it goes around my lower unit and must say it's pretty cool to watch. I have just the stock side water pickup and NO low water pickup like what Bobs machine sells.
    Where your red line is the water on my motor will hit the nose cone area just about an inch above the redline in your picture and the water then sprays up to or just above the yellow line. From your pictures I use to think the same dang thing but until I actually seen it with my own eyes how the water is traveling it really is pretty cool to watch but don't watch to long you'll be on the bank amazing how high they can be jacked with no lwp but the motor I'm gonna be building this winter will have a lwp

  6. #26
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    I'm with "Per" on this one. The water flowing out from under the stern shoots upward immediately and "is there" when the motor needs it.

    Jeff
    Attached Images Attached Images  

  7. #27
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    Good drawing Jeff I thought how could I do this but I have a hard enough time just posting a picture.

  8. #28
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    Default low pick ups

    Hi all,

    Sory I didnt catch this thread earlier, I love talking nose cones!

    Phill, I really think you would be fine just to make a two part filler nose cone. I race the 25hp and 550cc super sport outboard here in Australia and have run a full two part filler nose cone for five years now (raced it hard with no probs). The reason for low pick ups is if you wanted to get the torpedo level with water surface or above (like my 550cc- runing 1/2 inch above water) when at full go.

    I have gone to the trouble of adding low pick ups to motors before and found it to be a bit of a waist of time as a filler nose cone seems to to the job of pulling the water up to the factory pick ups just fine.
    All the guys here that race run a tube from the factory tell tale up to where they can see it (beside them) to make sure the motor has water.

    http://www.youtube.com/watch?v=7YX_8...yer_detailpage

    I hope thats some footage of my nose cone when we where testing, it runs hiegher now ans still feeds water with factory pick ups, see how the cone pulls water up the gear case.
    Attached Images Attached Images  

  9. #29
    phillnjack
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    Good video and very good picture.
    I can see what everyone is saying about the engine running in water that is comming up from the transom.
    But everyone also seems to be running with atleast 6 inches of setback !!!!
    with a setback yes the water level will be higher due to the water returning back to its original level.

    Also in the pick above the nosecone is pointing down, its definitely not running parallel to the drive shaft,is this
    for a reason ?

    can you tell me what benefits you have found by using a nosecone , ive never used one but realy like the look.
    do they realy give a noticable performance gain ???


    phill

  10. #30
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    Gotta admit, they look cool! As I understand it, below 60 mph or so they don't do much. Furthermore, the Yamatos never used a 'bullet' and are certainly competitive.

    Jeff

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