What Internal Corrosion Looks Like on a Suzuki Powerhead

Discussion in 'Outboards' started by SuenosAzules, Jan 3, 2016.

  1. SuenosAzules
    Joined: Apr 2010
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    SuenosAzules Junior Member

    I am writing this pertaining to another thread pertaining to internal corrosion and how outboard engine failures can be from multiple causes and not just one.

    This Suzuki 140 HP outboard engine owner complained of the engine only reaching 3,000 RPM when attempting full throttle. Upon inspection there was some signs of water in the oil when checked. The number four spark plug had rust on the electrode and the others did not. Upon disassembly of the head corrosion was sighted between the raw water jacket and cylinder number four where water was leaking into the top of the cylinder causing detonation which was causing a misfire in cylinder number four. If you notice the cylinder head it has literally been steam cleaned from the leaking raw water into the top of the cylinder. Corrosion can also be seen around other places in cylinder numbers 4, 3, and 2 if you look closely. This outboard engine only had about 700 hours on it when it failed. This failure was caused simply by the owner not flushing the outboard engine out after use continually causing the salt to remain in the raw water jackets around the cylinder head and caused corrosion from the jackets to the cylinders. The cost to replace this head and the rebuild the engine will be between $2,500.00 - $3,000.00.

    It is easy to get tunnel vision when a failure begins to occur on an engine. Thinking it is just one problem. If you look at this photo you can see multiple problems were occuring and the only peace of mind in this case was to tear down the entire powerhead to see to what extent the damage was.

    I hope this was helpful for those of you going through a similar situation with your outboard engines.

    [​IMG]
     
  2. missinginaction
    Joined: Aug 2007
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    missinginaction Senior Member

    Well, #4 is on the right in the photo and I think I can even see the beginnings of corrosion failure in the #1 cylinder (lower left of photo, just a tiny spot around those two water passages, outside edge.

    Flushing out salt water should be thought of just like wiping ones bottom or flossing your teeth.

    Just good mechanical hygiene.
     
  3. Mr Efficiency
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    Mr Efficiency Senior Member

    One of the key factors is the alloy used in the castings. I think Suzuki switched at one stage, where that engine sits in that time-line I couldn't say. Forum member Powerabout would possibly know more. It is well known that Mercury had an inferior alloy till some time in the 1980's when they made the change to a much less corrosion prone one.
     
  4. tom kane
    Joined: Nov 2003
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    tom kane Senior Member

    There is always a good case for fresh water closed (fluid cooled) outboard engines and any marine motor. It makes sense .Why do the keep doing it ?
    Google Images Johnsonator outboard.
     
    Last edited: Jan 3, 2016
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    For starters the weight of the engine would go up. Most outboards today are a big improvement on past corrosion problems, mainly due to improved alloys and coatings in the internal passages. Most commercial operators are a stranger to fresh water flushing, it is more likely a problem for users with long intervals between use.
     
  6. SukiSolo
    Joined: Dec 2012
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    SukiSolo Senior Member

    Could not agree more. The Japanese used a lot of recycled alloy for engine blocks in the late 70s' and 80s', at least on their motor cycle engines. You could never polish the castings (pressure die) whereas you could on European designed and made engines....;) Small Suzuki cars using alloy engines had quite a few problems with head gaskets and corrosion in the 80s' too.

    Of course the gasket material can also make a diference if it allows potential. Flushing is your best friend with outboards, but even car engines like a decent cooling mix 50/50 anti freeze/deionised water especially if alloy. Even more so if you like any core plugs to stay in place.....;)

    Thanks for the photo, a good reminder to those that ignore simple maintenance.
     
  7. CDK
    Joined: Aug 2007
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    CDK retired engineer

    How about a large outboard that remains in seawater the whole summer? It is tilted when not in use but there surely remains some water trapped. Flushing is no option there.
     
  8. Mr Efficiency
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    Mr Efficiency Senior Member

    The water drains out. It would be a design fault if it was pooling somewhere. You can flush the powerheads on moored boats with some outboards having a hose fitting for that purpose. The motor is not running of course.
     
  9. whitepointer23

    whitepointer23 Previous Member

    In au we call 1980's suzuki outboards disprins. They dissolve in water. And they had pressed cranks. If you hit a sandbar hard sometimes the cranks would twist and alter the timing forever so it would idle like a pig .
     
  10. whitepointer23

    whitepointer23 Previous Member

    Sometimes i run my outboards in a drum with a bit of truck wash and let it circulate for a while. The stuff i use has corrosion protection additives in it. Don't know if it really helps but it can't hurt.
     
  11. whitepointer23

    whitepointer23 Previous Member

    That new outboard with the chev v8 powerhead runs a closed cooling system so it can be done.
     
  12. Mr Efficiency
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    Mr Efficiency Senior Member

    There is supposed to be protective coatings on water passages, not much sign of that here. Zinc Chromate type of thing.
     
  13. CDK
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    CDK retired engineer

    Mine is a Yamaha F100, and yes it has a Gardena hose fitting. The only thing I do not have is a water tap within reasonable distance. The same applies to all boats in this bay and many other bays.
    My holiday guests hasten to flush their engines when the boat it back on its trailer. None of the locals ever do than, most even don't have a trailer. If they ever had internal corrosion problems, they didn't tell me about it!

    My guess is that this is a Suzuki flaw and more recent engines are cast from a more resilient alloy. Or maybe not, Suzuki's are quite rare here, most have Yamaha's or Mercury.
     
  14. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    my mates 100 yam after 5 years just ate through water passage to crankcase
     

  15. whitepointer23

    whitepointer23 Previous Member

    Was it on a moored boat pb or did it get flushed after outings.
     
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