Bayliner 175 cracked engine block

Discussion in 'Powerboats' started by DogCavalry, Feb 23, 2022.

  1. cracked_ribs
    Joined: Nov 2018
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    Location: Republic of Vancouver Island

    cracked_ribs Senior Member

    this sounds extremely likely to me - in fact the one Johnson 70 I have worked on (by coincidence, I know we're referring to the Yamaha here) ingested a plastic bag which blocked the intake on a long run back in to Bamfield. Nobody noticed until the engine began to sieze and smell funny.

    It got overbored, I forget by how much. Nothing crazy. We flattened the head back out by putting sheets of 400 grit sandpaper on a big piece of plate glass and taking off a few thou.

    IIRC it was a '76. It still fishes off the west coast of Vancouver Island, and the only difference is that it now makes a tiny bit more power than it used to, presumably because the freshly machined cylinder walls sealed a little better afterwards.

    Bottom line...you can have things go pretty freaking wrong, and still skate on major consequences.
     
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  2. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell . . . . .

    @cracked_ribs
    Great video and good advice as always, good on ya.
    That's a pretty cool set-up.
    I had no idea what pushing-in-while-turning the key did on those automatic/electric chokes.
    I have a feeling John's going to be watching a few of his videos.

    You don't have any insight as to what replacement plugs John should get now to save him a trip do you?
    He's going to need a year, model (and even a serial number perhaps) to be sure he's got the correct plugs and gap.
    He shouldn't assume the ones that are in there are correct.
    (Although if someone's done enough tinkering, and modifying, the ones that are in there may be preferred to stock.)
     
  3. DogCavalry
    Joined: Sep 2019
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    DogCavalry Soy Soylent Green: I can't believe it's not people

    Plugs for the Johnson I found online.

    Plugs Champion QL78YC; NGK BP28HS-10; Gap 0.030"

    For the Yamaha, it's going to be a good time. I'll be standing knee deep in water while I do it. A stony rocky beach, so I'm hesitant to let her dry out when the tide goes down.
     
  4. BlueBell
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    BlueBell . . . . .

    Depends how high the next tide is...
     
  5. DogCavalry
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    DogCavalry Soy Soylent Green: I can't believe it's not people

    Well, I'm far more concerned with damaging the hull leaving her on rocks and boulders.
     
  6. BlueBell
    Joined: May 2017
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    BlueBell . . . . .

    Some driftwood placed strategically may alleviate that concern.
     
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  7. cracked_ribs
    Joined: Nov 2018
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    cracked_ribs Senior Member

    Minor heads up: auto parts stores will ask if you want the NGK alternative etc.

    You do not! OMC stuff really prefers actual Champion plugs.
     
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  8. missinginaction
    Joined: Aug 2007
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    Location: New York

    missinginaction Senior Member

    I guess plugs are like motor oil. That said I run NGK's in everything I own. 302 Ford in the boat, 5.3L Chevy, Motorcycle, Both Hondas and a Volvo. Always had good luck with them. Champs might be OK too but the 302 in my Silverton is pretty similar to an OMC. Probably be fine either way.
     
  9. cracked_ribs
    Joined: Nov 2018
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    cracked_ribs Senior Member

    I have NGKs in my 302 as well.

    The OMC stuff likes the Champions because of the inductive resistor. You can get inductive resistor NGKs but it's the Z series IIRC, which are harder to find and more expensive than Q series Champions.

    And when you go to an auto parts store, they will tell you that the equivalent of the QL78YC is a BP28HS-10.

    But that has a carbon resistor which plays poorly with some of the OMC ignitions.
     
  10. BlueBell
    Joined: May 2017
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    BlueBell . . . . .

    Listen to cracked_ribs, there's a lot more to plugs than who makes them.
    Take note of the ones that come out not only their condition but are they all the same brand, model, detail.
    Do they all look the same service wise? Number them with a felt pen when they come out.
    Look for cracks, burns, corrosion, loose connectors, missing gasket, wear patterns, deposits, discolouration,
    physical differences, looseness in the block, the list is endless.
    I wonder what the manufacturer recommended then and now...
    And what the originals actually came with...

    Check that enrichener setting (video)
    Seems like a rebuild of that would be in order with the nifty kit shown.

    Fill with 50:1 or 60:1 (but no less) premium gold and then begin learning the "starting sequence" as Houston, Texas would say.
    Get that little puppy running, fix the 70, and you're away.
     
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  11. BlueBell
    Joined: May 2017
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    BlueBell . . . . .

    How are the new plugs working out?
    Did you get the engine going?
    How are you enjoying the new ride?
     
  12. DogCavalry
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    DogCavalry Soy Soylent Green: I can't believe it's not people

    I haven't tried the plugs. If it's not raining, I'm working in Vancouver, renovating the old apartment. There's a local engine mechanic who will work for reno work on his place.
     
  13. DogCavalry
    Joined: Sep 2019
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    DogCavalry Soy Soylent Green: I can't believe it's not people

    Since last we saw our Lime Twist, heroically delivered by @BlueBell, after @cracked_ribs incredibly kindly checked her out for us:

    Plugs replaced per advice above. Much improved!
    Automatic bilge pump installed.
    Complete replacement of electrical system.
    Spotlight
    New nav lights
    Windshield wiper, and window defogger tapes
    A new cover so that she's fully enclosed in the bad weather has been ordered and paid for - no more rainstorms in an open boat for us!

    Geordie, the stalling flooding issue was exactly what you figured. The red switch of vast importance.
     
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  14. DogCavalry
    Joined: Sep 2019
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    DogCavalry Soy Soylent Green: I can't believe it's not people

    Lime will be our ride for at least a year or three. Someday I'll get back to looking at her sister "The Lemon" but not any time soon.
     

  15. BlueBell
    Joined: May 2017
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    BlueBell . . . . .

    I would strongly suggest you get Lemon going and sell one of them now.
    Spring is here and the market is hot.
    The corrosion and blackberry entrapment will be horrible, it may already be too late on the corrosion front.
    Do it now and get rid of it for $$$.
    Time is not your friend on this one.
     
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