hi everybody I have a 70 hp Yamaha 3 cylinder 2 stroke and it has just cracked the alloy block long ways down the block threw to water jacket what would be your guys thort on welding it in place cheers
a.woodrow,
Feb 22, 6:54am
My thought is throw it away and get another one. Are you happy to do a patch up job on something that your life relies on and do you know why the block cracked in the first place?
mrcat1,
Feb 22, 6:56am
As above, throw it away and replace the block as a minimum otherwise if its that old that its split throw it away and get a newer outboard.
seanlou,
Feb 22, 7:13am
its not that old just spent over 3 grand on a rebuild but think I may have over talked it
martin11,
Feb 22, 7:17am
Its scrap now do not try welding it .
xs1100,
Feb 22, 7:18am
its a bake bean can now sorry,try to source a good 2nd hand one on here
If you have just spent over $3000 you may have some redress if you had a dodgy rebuild
martin11,
Feb 22, 7:41am
Did you do the overhaul yourself ?
seanlou,
Feb 22, 7:50am
yea I did it ma self its a 1990 Yamaha tried drilling crack as its olny a hair line crack and put jb weld high temp over it and it lasted a wee bit but now its a bit big ive spent to much to just toss it and buy new engine wish I culd tho we olny use it on the lake in Cromwell as its our first boat
mrcat1,
Feb 22, 9:06am
What? you spent over $3k on a 70hp rebuild, I was going to rebuild a 225hp Johnson with new pistons, seals, gaskets, rebore, new VRO pump and having a shop do it and that was going to be $6500.00, and for $9k I got a lot newer with only 300hrs on it fitted and all running set up ready to go with a warranty, sometimes your better to cut your losses and get something newer.
gmphil,
Feb 22, 9:49am
well if u going to do this after spending u don't want to toss more away. is remove head take to shop get checked in welded as per like a car ?
shakespeare6,
Feb 22, 10:16am
If it's only the out side of the block through the water jacket, yep weld it in place. Your no better off if it doesn't work. Did it to a v6 johnson 10 years ago which is still running strong. Tig welded by an engineer ends drilled to stop the crack running. Cracked up by a stud when trying to remove it.
elect70,
Feb 22, 10:25am
Buy a used block or complete motor . . once sea water gets into the internals its a knacker . happened on a 90hp suzuki i had luckily I bought used top section .
seanlou,
Feb 22, 11:24am
yea mine cracked right by a stud from over tighting I think yea it just cracked down the block and leaks water from water jacket was thinking of welding as it cant get any worse than it is nw just to keep it running for the rest of summer then try find a block to rebuild it as all parts inside engine are new
mrcat1,
Feb 22, 11:30am
You realise that you can buy a very good quality torque wrench for a few hundred dollars and would have saved you from this issue.
daryl14,
Feb 22, 11:45am
You could pull it apart and sell off any good parts out of it. Or perhaps look offshore for a good empty block to build up.
m16d,
Feb 22, 3:44pm
Outboard motors make good letter boxs. just saying.
tsjcf,
Feb 22, 4:41pm
Got any good welders in your area have a talk to them. Tig maybe if you strip the block or something like these for repairing in place. http://www.aluminumrepair.com/
mechnificent,
Feb 22, 6:41pm
Ha. Yhose guys reckon those rods can braze zinc, and that the rods melt at 720ish degrees. Zinc starts to melt at about four-hundred and something degrees. Something funny there. I don't think I'd trust what they say. Though, there are some good aluminum braze rods about, slightly softer than aluminum but they flow and stick really nicely.
Another thing I'd mention to the OP too is. That crack. It won't have happened I don't think JUST because you torqued it wrong. Aluminum is pretty soft stuff and doesn't crack that easily, and if everything was flat and fitting nicely it shouldn't have cracked even with really varying torques. I'd be suspecting there is something else going on. Perhaps the bearings weren't seated right and there was a gap between the cases, or something was warped from taking it apart. Also, if you have a crack that goes right through into the water jacket, and you weld on the outside only, there is going to be a crack still in behind the weld that will get corrosion in it, and eventually cause pressure that will recrack the cases. If you want a weld to last you need to grind right through and weld from the inside surface right back up to the outer surface.
I reckon you should try finding a second hand set of cases. There are outboard wreckers about. There is one that sells parts on TM.
elect70,
Feb 23, 8:27am
Trouble is castings arent good alloy made from all sorts of crap metal , trying to weld it would be a nightmare . If going to try fixing use something like that fibre glass stuff that has metalic fibre in it , if its just the water jacket its not under hi pressure .
seanlou,
Jun 2, 6:52pm
thanks every 1 for your input but have found a new block so fixing nw thanks
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