Cracked lower unit on Yamaha Outboard

Marcevo190

Hi All,

I inherited an outboard which has a crack on the lower unit casing. It extends from just after the prop but not as far as gear/oil housing (prop to exhaust).

The cause was the outboard big stored tilted up, with water in the exhaust chamber water which caused the crack through freezing (repeated expansion/contraction etc..)

I have been advised welding is an option but at significant cost as the gearbox will have to come out due to heat of the Weld. The other options I have it's to apply a large jubilee clip to support the crack or drill a 2mm hole just after the crack.

My current solution is to do both jubilee and drill - although I'm unsure if doing both are a good idea (isn't it one or the other? Any assistance would be appreciated here.

Ideally I'm going to price around the Weld option and hopefully get lucky!

I will try ans post a picture tomorrow.

spaceHopper

Can you get a second hand part at a good price?

Marcevo190

spaceHopper wrote: »

Can you get a second hand part at a good price?

I'd need a full lower until and have been quoted around 1k so it's not economic.

fergal.b

If you weld it you will have to strip the gearbox as the heat will melt the seals, best bet would to dill the holes and with a dremel grind a little grove along the crack then fill with something like JB weld https://www.proweld.ie/product/jb-weld-marineweld-epoxy-twin-tube/?gclid=Cj0KCQjw0ejNBRCYARIsACEBhDOzi4y463VKzuhPwDF5929bDVdx_TwYY-1hnyE0N_isxEn1v59G7EYaAtGQEALw_wcB or a metal repair paste, you could also add a jubilee clip.





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Marcevo190

fergal.b wrote: »

If you weld it you will have to strip the gearbox as the heat will melt the seals, best bet would to dill the holes and with a dremel grind a little grove along the crack then fill with something like JB weld https://www.proweld.ie/product/jb-weld-marineweld-epoxy-twin-tube/?gclid=Cj0KCQjw0ejNBRCYARIsACEBhDOzi4y463VKzuhPwDF5929bDVdx_TwYY-1hnyE0N_isxEn1v59G7EYaAtGQEALw_wcB or a metal repair paste, you could also add a jubilee clip.





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Would it be a good approach to apply all 3 methods. Drill a 2mm hole, dremel the crack, apply marine epoxy and immediately apply a jubilee clip?

Or is there possible structural conflicts

fergal.b

Yep that should be fine, use a stainless steel clip.




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rodey

yep the way ur thinking of doing it should be ok as long as the crrack isnt gone near the actual gearbox hub is,
what outboatd is it anyway, ii break a good few outboards as 1k sounds alot unless its a prity new one

Marcevo190

Marcevo190 wrote: »

Would it be a good approach to apply all 3 methods. Drill a 2mm hole, dremel the crack, apply marine epoxy and immediately apply a jubilee clip?

Or is there possible structural conflicts

Just wanted to give an update here. This has worked far better than expected. We've had the boat out twice and the repair is holding (Belzona type compound)


http://i50.photobucket.com/albums/f309/Marc_Ronan/Mobile%20Uploads/IMG-20171022-WA0005_zpslhbzzrg4.jpg

Unfortunately, another issue has popped up. The tell tale has stopped streaming water. I've removed the cowling and confirmed no blockage in the water line between the tell-tale and main block.

I removed the lower unit and shot compressed air up the water line and air was coming out the tell tale as expected.

I've stripped the water pump housing and think I've found the issue. There seems to be corrosion under the housing and I'm not sure if this is causing the issue.

My only other theory is that the main block may be backed up. I tried running descaler through the main block but nothing. So I think I may be loosing pressure due to corrosion of lower unit

Opinions welcome!

http://i50.photobucket.com/albums/f309/Marc_Ronan/Mobile%20Uploads/20171105_111248_zpsz2lgl3gx.jpg

fergal.b

I can't see the photos but I'd say the problem is the impeller is not getting a good seal with the corrosion.






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Marcevo190

fergal.b wrote: »

I can't see the photos but I'd say the problem is the impeller is not getting a good seal with the corrosion.






.

Thanks for heads up - updated with direct links.

Steve

Fixed the images for you.

Marcevo190

Steve wrote: »

Fixed the images for you.

I'm from a period of time when photobucket didn't require an upgrade for 3rs party hosting

Stripped the housing back fully and exposed true extent of corrosion.

http://i50.photobucket.com/albums/f309/Marc_Ronan/Mobile%20Uploads/IMG-20171107-WA0018_zpsrijzaqnd.jpg

35 euro later a new part ordered for delivery next week

Steve

Best of luck with it! Hope that sorts it.

imgur.com is easier for hosting pics for forums and its free.

https://imgur.com/