Ski boat project questions

Discussion in 'Powerboats' started by aussiebushman, Sep 22, 2012.

  1. aussiebushman
    Joined: Oct 2009
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    Location: Taralga NSW

    aussiebushman Innovator

    I got a bit deeper into the Seloc manual. I was wrong about replacing the sleeve itself - they are an integral component of the cylinder so they must be honed or bored, but Tunnels and P are correct - one cylinder can be done without the others. 0.015 " (0.38 mm) oversize pistons are generally available (but not for all models) and are approved by APBA. The weight difference between the standard and oversize pistons is said to be insignificant.

    Alan
     
  2. tunnels

    tunnels Previous Member

    Yeah that amount of oversize its really just a clean out like you have with a scored bore . Its better to bore it rather than hone it . little more exspensive but you get a round bore again !! like i said twostroke motors seals and gaskets have to be absolutley 100% sealed every where !! check the reeds very very carefully as well !! read about themin your manual if they dont seal properfly can cause hard starting and rough idle and just above idle !!.
    Keep up the good work !!:p
     
  3. aussiebushman
    Joined: Oct 2009
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    Location: Taralga NSW

    aussiebushman Innovator

    Yes

    The inner bearings on the crankshaft feel good. The reed blocks seem very loose around the crankshaft but that may just be due to the last owner partly disassembling them. The manual is excellent in terms of the procedures for testing, cleaning, reassembly etc.

    I'll certainly have to replace the needle bearings in the con rods (these are the caged type), rings, lockrings, seals, gaskets and o-rings. The potential amount of work is daunting, but the result should more than justify the time and cost . It will also keep me from stealing hubcaps through boredom. (They are getting hard to find here in the bush anyway)

    Alan
     
  4. tunnels

    tunnels Previous Member

    I like your sence of humour !!
    Yes i can imagine it a frightening looking job on one of those long 6 cylinder motors But laid out properly and in order of assembly it should be a large piece of cake , a light smear of Molly grease to make sure eveything have slip when the motor first fires up is what i used to use . Long time ago moli grease and oils were the things to use and really helped i i used to swear by them . now days it synthetic oils etc . My own out board i only use the mercury 2 stoke oil nothing else !!I tried using the outboard oil in my mower and the plug oiled up before i finished the lawns ! so found shell 2 stroke was the only thing for the mower .Injected motor oil is quite differant to premixed and the acuracy and consistancy of the mixes is really important !! have watched some guys just pour it in and never measure at all !! shell be right mate !! always the ones at the ramp having problems getting there motors to started and when they do get going you can see the clouds of smoke as they slowly dissapear over the horizen !!
    Take care :D
     
  5. Frosty

    Frosty Previous Member

    When the engine was stripped were parts numbers 1 2 3 4 5 6

    015 can not be honed. a hone will not remove that much and a hone was never meant to. A hone puts tiny cross hatch marks on the bore to hold oil to seal the rings its not a metal removal tool.

    New parts on old surfaces ---your a brave man.
     
  6. tunnels

    tunnels Previous Member

    No just one cylinder will need to be bored and fine hone the other five to bed new rings !!. :)
     
  7. aussiebushman
    Joined: Oct 2009
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    Location: Taralga NSW

    aussiebushman Innovator

    Yes Tunnels - precisely. I feel much better prepared to tackle this job now because the advice on this forum has generally been excellent - with the exception of one poster who is invariably negative about everything.

    Regards

    Alan
     
  8. tunnels

    tunnels Previous Member

    we all here t help with anything and there is quite often some really good advise ! have a little fun as well !
    Have a good weekend !
    ;)
     
  9. Frosty

    Frosty Previous Member


    Yes im a little cautious because it is my job and has been since I left school . If your not trained in this respect and all you have is a ---good aptitude for mechanical engineering everything seems fine. Experience with building engines for a living has tought me not to be.

    Old outboards dont overhaul well threads suffering damage is one of the main reasons but you havnt go to tighhten anything down yet.

    If you go to the nearest marina work shop you will see many complete engines thrown under the bench of experienced engine builders --why do you think that is when they can just rebuild them and make money.

    Half building an engine with old and new parts is 50-50 chance -- Im not guessing at this.

    Qualifications Mech E, F tech IMI , IRTE I used to be asked to give professional evidence ( opinion) in court. You got it for free.

    But if you feel confident with others optimism go ahead. I did tell you before you bought it.
     
  10. tunnels

    tunnels Previous Member

    Negitive thinking !
    You need a change of food !! your diet affects your thinking and you health !! change of enviromant, change of food ,even a change of life style , and not forgetting ya undies change them as well and i dont mean turn them inside out and back to front !!:p.
    He bought a motor yes its a oldie yes and possibly a goodie i hope !!so lets help with advise and if things are a little the worse forware see what we can come up with to repair it !or find a way to replace the bits !! :D
    Nothing is impossible nothing at all !!so get on with it !!:p
     
  11. Frosty

    Frosty Previous Member

    Nothing impossible!!! well bolting a rotten old outboard and torquing the heard down on white crusted threads is pretty well near up top of the impossible list.

    A bit like the How do I get back to earth from heaven jokes,--- Jesus says you have to overhaul a old 6 pot Merc bought in a cardboard box. Hows that for negative.

    Ok what to do-- Put the engine together,-- carfuly soak the whole thing in deisel and check out and count all the bolts. Build the engine case completely without crank and pistons, water jackets everything. If it all torques up then I might be a bit more confident in your investment. ( don't torque to full torque)

    Crank ball bearings have play --new ones have play. Thing is do they growl.

    They need replacing. Don't us RTV silicone arrghh.

    There are professional gasket gunks. I use shilac or Hylomar.
     
  12. aussiebushman
    Joined: Oct 2009
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    Location: Taralga NSW

    aussiebushman Innovator

    Thanks Tunnels.

    In business as well as private life my motto has always been "Don't tell me what cannot be done. Show me a solution" Usually, even the silliest suggestion, however improbable, difficult, or expensive will generate other ideas that work
     
  13. powerabout
    Joined: Nov 2007
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    Location: Melbourne/Singapore/Italy

    powerabout Senior Member

    wasnt this an inline 6?
    no cylinder head
    oem gaskets are pre cemented so you dont use anything if you do they will fail ( on ones that are pre cemented that is)
     
  14. tunnels

    tunnels Previous Member

    Good boy frosty good boy !! See its not that hard at all is it !

    Last time i played with a old out board i used taps and carefully redid all the threads and cleaned and blew all the grot out of the holes then used threaded rod and cut to the right length and screwed that in and bedded it down with epoxy new metal ( goes reall hard and can file it )and drilled into the rod and pined that threaded rod as well . the motor is still going after 10 years ! got nuts and washers instead of bolts !! just make sure theres some good moly grease on the threads and keep using wd40 on the motor its self and no rust or corrosion any where .
     

  15. aussiebushman
    Joined: Oct 2009
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    Location: Taralga NSW

    aussiebushman Innovator

    Yes it is an in-line 6

    Yes "Powerabout" spot on.

    It is an in-line 6
    There is no cylinder head as such
    Yes OEM gaskets will be used without additional sealant
    All of the bolts are in good condition, no sign of corrosion.
    If there is a problem with soft metal in the block, I shall do exactly as Tunnels says (I have done this before) and bed in new studs with epoxy

    Per my last post, positive suggestions are always welcome. Even if not adopted, they usually point to an alternative solution.

    Cheers

    Alan
     
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