Cracked lower unit, repair help.

Nandy

Commander
Joined
Apr 10, 2004
Messages
2,145
Well, I did something stupid. I was taking the lower unit in this used 70 hp Evinrude that I bought. I tapped with a hammer and a piece of wood, then went from tapping to hammering and that caused this:

106_3514b.jpg

106_3513b.jpg


Ok, save all the screaming for later, I know it was stupid? Anyway, I do have an oxyacetylene torch but this lower unit is not steel which is the only thing I have weld as I am self taught. I have done a few things with cast iron. Generally you need to preheat cast iron before you weld on it. I don?t have the oven so I have taken my chances and come successful. What alloy is this lower unit? Has anyone here successfully repair such failure welding it back or should I just hammer the part back to the original position and marintex it?

Any help will be appreciated.
 

flabum

Chief Petty Officer
Joined
Feb 17, 2007
Messages
567
Re: Cracked lower unit, repair help.

There is no stress at that point, so fill the crack with JB Weld or Marine Tex and tap the casting back into place and finish fairing with the epoxy.

You can also take it to a welder.


your choice.
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: Cracked lower unit, repair help.

The welder would have to TIG weld it with argon, fill, then re paint.
 

Nandy

Commander
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Apr 10, 2004
Messages
2,145
Re: Cracked lower unit, repair help.

Hmmm, I needed an excuse to get me a tig rig, unfortunately, im kinda broke now... ohhh well, another time. I think it will be jb weld.
 

flabum

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Re: Cracked lower unit, repair help.

Christmas is in a couple days......good excuse to max out the card :0)
 

tashasdaddy

Honorary Moderator Emeritus
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Nov 11, 2005
Messages
51,019
Re: Cracked lower unit, repair help.

the inside looks like heck. was it a salt water motor?
 

Nandy

Commander
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Apr 10, 2004
Messages
2,145
Re: Cracked lower unit, repair help.

Yes, they ran it on saltwater a bit more than what I was told. All the screws has oxidation on it. When I took all the screws from the lower unit out it was an ordeal. Then the lower unit had absolutely no clearance for me to pry it. It was not until the last blows that it got me enough clearance for me to get my screw driver and put several pounds of my weight to get it to release. I have rebuilt all 3 carbs, put the new enhanced water pump and now I am ready to install the telltale for the water. I will take that water jacket out as the idea of metal running drifting in the cooling system does not appeal to much to me. I will then drill and tap the hole for the connector. Also got the thermostat to change. Im afraid those screws will be the same... I will use my friend heat to loose them.
Thanks y'all!
 

Sherman

Petty Officer 2nd Class
Joined
Apr 19, 2003
Messages
173
Re: Cracked lower unit, repair help.

You could repair it with a product called Alumite see at Alumite.com. I used it to repair alum. castings with success. Can be applied with a propane torch but your gas welder will be better.
 

samo_ott

Vice Admiral
Joined
Jun 18, 2006
Messages
5,125
Re: Cracked lower unit, repair help.

I used something like Alumite to weld my 5.5hp LU a few years ago after I left water in it in the winter and it worked well. Only needed a propane torch. I think it was a different name up here though.
 

Nandy

Commander
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Apr 10, 2004
Messages
2,145
Re: Cracked lower unit, repair help.

enhanced waterpump?

Evinrude had a new water pump for these motors and that is how they refer to it. There are several differences between the original pump and the new one. The original one is a one piece cast and I have no idea what type of material, but it looked all ate up. The new enhanced has a 2 piece metal jacket, the housing is made out of plastic and a few other minor changes.
 

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,385
Re: Cracked lower unit, repair help.

Tig weld would be the best way to repair and then refinish but as said above you can use any of the other and less troublesome methods. If you do decide to tig weld it then let me know if you need any help with the set up and settings.
Good Luck.
 

Benny1963

Lieutenant
Joined
Sep 17, 2006
Messages
1,476
Re: Cracked lower unit, repair help.

tried a few things on mine brazing with alum 2000 rod and also a couple of other things cheaper ,with less than sastisfactory results .took and had welded tig with argon then cleaned up weld with small grinder repainted
stonger than new .
it cost me one hours labor at prop shop 60$
BENNYB
 

Lakester

Chief Petty Officer
Joined
Nov 17, 2007
Messages
428
Re: Cracked lower unit, repair help.

hello nandy,

have u considered possibly a fiberglass repair? u may be able to drill both sides of the crack, once u have reset it, then work in the glass to the holes u drilled so that u have a glass to glass bond in lieu of betting on an alum to glass bond.

done with care, my bet is it will hold and keep broken cavitation fin stabilized. may not be best for resale, but if that was the issue, i would alum weld it. tig. but u may want to take ur pix to a shop that does that kind of welding for an opinion...

some cash and a six-pac may get it done to bead level in min time cost. u can dress it and repaint.

hope u will let us know what u did and how it turned out.

regards, and good luck.

lakester :cool:
 

Lakester

Chief Petty Officer
Joined
Nov 17, 2007
Messages
428
Re: Cracked lower unit, repair help.

hello,

also:

well, i would be lying if i said i havent seen any dry corroded bolts, or bolt holes on any of the parts on my 1971 85HP evinrude.

ur holes look to me to be very dry. did you put any oil, or liquid wrench on them before whacking the l/u downwards? did u let them soak over nite at least? oil and soak fresh before any heavy hand applied?

i like to tinker with coleman lanterns. some parts have heated and cooled for over 60 years and are a bear to crack loose! when guys ask how to do this or that... oft the reply is:

etc, etc.... and also we use a lot of patience. so sometimes soaking for several weeks can be an important procedure.

it is easy to beat a part into submission... but it is an act of finesse to outsmart the part... and with patience and intelligence... render it into submission.

but as we all know, sometimes it is impossilble. for those sad times, destruction can be the only solution at hand worth considering. sometimes too far gone, is just... too far gone.

regards

lakester :cool:
 

Nandy

Commander
Joined
Apr 10, 2004
Messages
2,145
Re: Cracked lower unit, repair help.

I will let you guys know what I do. Probably I will have the rig in the water and see how it performs before putting more money on it.
 

Lakester

Chief Petty Officer
Joined
Nov 17, 2007
Messages
428
Re: Cracked lower unit, repair help.

hello,

well, if it was mine... i dobut id run it that way. the least i would do is: gently try to reset it, then make a small V along crack on both sides and put in some jbWeld epoxy. dress it down some, add some paint... and for my bet, until further notice...

forget about it. :confused: [crack? what crakck"?] :confused:

just monitor it. even to feel it after running it [engine shut down ]

will be interesting to see how u handle it. :)

regards
lakester
 

Gary H NC

Fleet Admiral
Joined
Dec 1, 2005
Messages
8,972
Re: Cracked lower unit, repair help.

JB Weld bonds very well to the cav plate.I have used it to fill holes from Hydrofoils and fixed a cracked top gear case cover on an outdrive.
Even used it on a thermostat housing on a big block Chevy engine.It has never failed me.It sands down and paints well too.I would JB it and never worry again...
 
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