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Old 07-12-2006, 06:05 PM
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Default To all you tech`s out there...

...that has seen everything!
What has happened here? This is a 250hp V8 Johnson '94
There are long cracks in the lower where the shifter axle goes.
Anybody know what could have caused this?
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Old 07-12-2006, 06:48 PM
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Default Re: To all you tech`s out there...

thats a new one.........


impact maybe ????


if you figure it out let us know
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Old 07-12-2006, 07:01 PM
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Default Re: To all you tech`s out there...

I can tell you this much, first we tought is was the frost that had taken it over the winter. A good welder fiksed it this spring. Then today the guy got back to the welder with the housing, it had cracked agein... but not where the welds was, just beside. I know this welder wery well and he is THAT good! No way he has made a mistake. But as you can see it has hapend agein, no mechanical force or stress. I am just a big ?

BTW: The crack is outwards!!!! no impact, no scratches on the paint...

Last edited by Hydrolift; 07-12-2006 at 07:05 PM.
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Old 07-12-2006, 07:21 PM
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Default Re: To all you tech`s out there...

I am not saying that I know what caused the original crack. However, I have seen cracks form right next to a welded crack. The weld doesnt crack, the area adjacent to it does. Especially, aluminum.
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Old 07-12-2006, 07:28 PM
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Default Re: To all you tech`s out there...

I would agree if it wasn`t for the way the crack is. What you do not see to good in the picture is that the crack is outwards. It`s like somtehing has pushed it outwords and stretched the metal until it cracked. It`s out about 1cm in the middle and 2mm by the crack.
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Old 07-12-2006, 11:17 PM
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Default Re: To all you tech`s out there...

Total stab in the dark, but it may be some slop or vibrations in the driveline causing undue stress on the bearing housings (ie what is cracked)

I've seen similar damage in totally unrelated applications (industrial equipment, motorcycle) cause cracks in supporting housings. I have an old harley that when I purchased had a totally unbalanced motor, and the vibes caused the stator (alternator) to fail every 2500-3000 miles, like clockwork. Many other parts, including frame and motor mounts (both steel) cracked regularly due to this. NO problems whatsoever after motor was properly balanced.

Does the motor vibrate or shake more than usual?

Possible causes of above theory are bent driveshafts, unbalanced (damaged) props, unbalanced powerhead, bad bearings, etc.

Last edited by jmherbert; 07-12-2006 at 11:23 PM.
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Old 07-13-2006, 07:19 AM
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Default Re: To all you tech`s out there...

Naaaah! That unit has a streamliner nose cone welded on and faired. Just a crappy job.
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Old 07-13-2006, 07:28 AM
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Default Re: To all you tech`s out there...

seen it many times like that. there is a water cavity there & if it doesn't drain because of mud usually it will freeze & break. why it happened again is another thing.
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Old 07-13-2006, 10:56 AM
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Default Re: To all you tech`s out there...

I would guess water freezing for the first crack, was the drive exposed to freezing temps? I filled mine with resin to fill the void and re-installed. If the drive actually cracked wouldn't oil be seeping out?

Last edited by czy40p; 07-13-2006 at 10:59 AM.
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Old 07-13-2006, 08:01 PM
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Default Re: To all you tech`s out there...

No, it was not exposed to freezing temp. so we can role that out once and for all. The oil was changed an the old oil looked good.
I have been in contact with the importer and their tech. he said it could be oil pressure building up and make it crack, is this a plausible reason?
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