prop problem??

Discussion in 'Outboards' started by razbarb, Apr 15, 2007.

  1. razbarb
    Joined: Apr 2007
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    razbarb Junior Member

    Hi all, i'm new to this forum and to boating.
    I own a 13" tinnie with an '82, 25hp suzuki outboard, which has replaced an 18hp Tohatsu that was originally on my boat.
    I gingerly drove the 25 for the first time ( was told by my local boat mechanic that it was no good).
    It idled fine provided i held some revs with the grip.
    It was well and truly warm when i opened the throttle and it just seemed to slip. Like driving an auto trans that is playing up.
    The prop had a lot of nicks and dings on it, so i filed it smooth and hammered out the dings.
    I'm not experienced at this so i made sure the blades looked equal after filing.
    I repainted the prop to see where the paint would wear off first and it wore off of the front (face closest to boat).
    Bearing in mind that i only opened her up twice so the wear happened while revving it or idling up the channel from the ramp.
    I checked the prop at home and when i turn it, the prop seems to wobble slightly. There is also a little endplay in what i imagine is a shaft that the prop bolts to.
    My boat also has an extension welded to the transom to raise engine height by 3", which didn't create any problems when the Tohatsu was on.
    I apologise for being long winded, just trying to give some background.
     
  2. Bergalia
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    Bergalia Senior Member

    Prop problem

    The 'nicks and dings' provide a clue. What caused them ? Did its previous owner allow the prop to meet with something nasty underwater - a rock perhaps. Even drop it on a concrete surface.That's my guess.
    Sounds like it may have done some serious internal damage which you'll only discover by stripping it down (not a highly technical job) A basic tool kit will do it. And then look for which part of the shaft is prone to 'wobble'.
    If it's not too serious your local garage should have the jigs to 'straighten it out'. By the way, it's not a good idea to try and hammer out 'dings'. Props are balanced items - and you may have beaten it out of kilter - which will only exacerbate your 'wobble' and eventually 'wobble' your engine to bits.
    Sorry to be a Cassandra - but best check it out before you do irrepairable damage.
    :( :( :(
    Oh, by the way - welcome to the forum.
     
    Last edited: Apr 15, 2007
  3. razbarb
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    razbarb Junior Member

    Thanks for replying, not a Cassandra at all.
    Thanks for the advice.
    I stumbled onto this forum last night and the knowledge and advice present is great.
    I have been told so often that outboard motors are untouchable and too complicated to maintain at home, so i'm on a mission to learn.
    At my own expense!!
    I was also told by a marine mechanic this outbopard was stuffed and he offered to not charge his labour if i left it with him.
    I'd like to see if my gut feeling about this bloke is right.
    So thanks again.
     
  4. Bergalia
    Joined: Aug 2005
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    Bergalia Senior Member

    Prop problem

    Razbarb - bear in mind - anything made by man, can be 'unmade' by man.
    Sure those with 'vested interests' ie the manufacturers and 'specialist' merchants will tell you that it needs 'specialised tools', 'specialised knowledge' etc. ********. An outboard is your basic two-stroke or four-stroke engine. The only difference to the motor that keeps a mo'bike, lawnmower, or portable generator chugging, is its linkage. Anyone who's tinkered under the bonnet should have a good idea of how it works - and have the tools to handle it. You're an Aussie Razbarb - by nature you'll have 'cut' your teeth tinkering. And while you're at it it's worth de-coking to make it purr sweetly. The only real bugger will be those stupid (world's worst invention) 'Phillips' screws. Rip em out, use them as fishing weights and replace with Allen screws.
    Go for it 'blue' and keep me posted.
    :)
     
  5. marshmat
    Joined: Apr 2005
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    Location: Ontario

    marshmat Senior Member

    As an '82 your motor is old enough that it's probably not loaded up with computers, which is the main reason the modern ones are a pain in the butt to service. The engine itself is neither complicated nor untouchable. If you can repair your lawnmower engine, and can read (and follow!) a shop manual, fixing this puppy up is well within your ability. Get the book for it (the mechanic's shop manual, not the owner's manual), see how it goes together, clean it up, and get to work. Best to get it in prime shape now, rather than have it crap out mid-river.
    As to your slipping/prop issue. It sounds like your prop is actually coming out of the water when you gun the throttle. Where does the plate above the prop sit, relative to the bottom of the boat? (If it's substantially higher up, the prop might be coming out of the water when you accelerate.)
     
  6. Bergalia
    Joined: Aug 2005
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    Bergalia Senior Member

    Prop problems

    Told you it was easy - even the Canadians can do it...:D
     
  7. SamSam
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    SamSam Senior Member

    It sounds like maybe the hub is ''spun''. There's the splined part of the propellor that slides on the shaft and then a rubber ''hub'' that is pressed between the splined part and the propellor itself. It takes the place of the older type shear pin. Yours has maybe been stressed to the point of the rubber hub letting loose. It's got enough grip to let you idle along but when you give it throttle the shaft slips. Unhook the spark plugs and put the motor in gear and see if the prop will turn without the shaft turning. You can take it in and get it replaced or get another prop. Or you can borrow a prop and see if a different one works. Sam
     
  8. marshmat
    Joined: Apr 2005
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    marshmat Senior Member

    I seem to be surrounded by Aussies :eek:
    Somehow though I don't feel my country's honour is at stake this time around. I suspect if we just send a freighter of assorted Canuck beers down under, we can resolve these old Commonwealth rivalries peacefully.....:cool:
     
  9. Frosty

    Frosty Previous Member

    Berglia is quite right these people that study at technical colleges and go through long tedious apprenticships are waisting their time.

    All you need is a bloody big hammer --"if in doubt give it a clout" I always say.

    Tools --bulshit a chisel will get you through most things. Why they make special tools for stuff is just to confuse you.

    Tolerances --crap---your not hitting it hard enough.

    Yep,-- what can be done by technicians can easily be undone by the man in the street.

    Jeeees
     
  10. Bergalia
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    Bergalia Senior Member

    Prop problems

    Off at a tangent, but Tuan Frost's remarks remind me of a great cartoon which showed a couple of lab technicians watching a gadget whirl and squeak. One turns to the other and says: "Well - it works in practice...But will it work in theory..." ;)
     
  11. Frosty

    Frosty Previous Member

    I used to make good money out of big hammer people.

    "Oh eee,---ive had a look at it myself,---ive checked everything, Im a good mechanic me,--me dad taught me on Sundays,--I did me dads brakes for im on the car once,-- just before he commit suicide driving over the cliff.

    Ive definately fixed it but it does'nt seem to werrrk, and its smoking and banging a lot.
    Jeeees
     
  12. razbarb
    Joined: Apr 2007
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    razbarb Junior Member

    Are you suggesting i'm a big hammer person?
    I like to do my damage with lots of small hammers, and spell correctly as well.
    I'm happy to part with my hard earned for honest advice and workmanship. I don't like my lack of experience being exploited by less than honest people whether they "waist" their time doing apprenticeships or not.
    Obviously you"re enough of a prodigy not to learn by trial and error.
    I'll happily play with my hammers and sharp chisels.
    I'm with you Bergalia, i'll try my practice before my theory.
     
  13. razbarb
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    razbarb Junior Member

    Oh and thanks for your advice guys!
     
  14. razbarb
    Joined: Apr 2007
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    razbarb Junior Member

    A beer would be nice marshmat.
    Do you have VB over there?
     

  15. Frosty

    Frosty Previous Member

    I should have put Berglia at the top .--My comments were to Berglia.

    Athough I see your point, when you open a thread it does seem to wander a little. Dont be too put off by people sidetracking a bit off your original question. It happens a lot.

    The spelling was to suggest an accent and perhaps a little bit of humour.

    My apologies.

    By the way you have whats called a blown prop.

    Your mechanic is probably right. Its likely he went to technical college.

    You could smash the crap out of it with a hammer!!! That might work.?
     
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