Aluminium Lower Unit Repair

[FusionKing]

FK,
There is more to the story then anyone outside of the companies knows. Anyway this is getting off topic

I know more about this subject than most folks...

And I agree...way off topic

[LA Weld]

I left a 1/8 gap with 45 degree bevel on both sides.

This was a recommendation from Mercury Performance that provided the replacement piece.

I did leave as much of the original structure, so I did not follow the recommendations to the letter. Mercury Performance wants you to cut down to the housing. I don't like that and feel it would guarantee a catastrophic failure if the lower unit was to be damaged again. My thinking is the machined part would rip the housing as to its material strength.
The weakest link being the casting, so you can follow my thought.

Craig, here is a coupon from many many years ago. It was a training piece I did when I finally felt I could do it. It reminds me of where I came from and the GOOD OLD DAYS PAST!
I gotta say, I was way to full of it then. How owning your own and growing up has it drawbacks...

Good luck, just be patient.

[Agcadmin1]

The mercury I had catch on fire was a verado five years ago. Motor had 500 some hours on it. It had an electrical short somewhere in the motor I suppose
did quite a bit of damage to the wiring harness and burnt the hood on the outboard up bad. As for the difference in the castings on the lowers of yamahas I have absolutely no idea what the specs are. i know there a great motors and very durable in my opinion. My regulator has 1500 hours on my four strokes with no problems.

[FusionKing]

I left a 1/8 gap with 45 degree bevel on both sides.

This was a recommendation from Mercury Performance that provided the replacement piece.

I did leave as much of the original structure, so I did not follow the recommendations to the letter. Mercury Performance wants you to cut down to the housing. I don't like that and feel it would guarantee a catastrophic failure if the lower unit was to be damaged again. My thinking is the machined part would rip the housing as to its material strength.
The weakest link being the casting, so you can follow my thought.

Sounds like it worked out well (Nice work btw) That is pretty much how I do it as well.
I never much cared to cut off the remaining skeg either.
I have repaired about as many poorly welded skegs as freshly damaged ones it seems sometimes. They seldom have 100% penetration and are always welded/spliced in a straight line. Sometimes you have no choice tho.

[Craig in Denver]

The gear oil is Synthetic and the area that is exposed to heat is far enough away that a soaked rag is placed there to monitor and keep the temp in check. It never gets hot enough to steam, therfore less than 210 degrees.

I meant to comment on this. Last summer, I took my dual sport Suzuki DR650 for a jeep road ride. Oil temp hit 272*. I was glad to be running synthetics. No steam, <210*, is a good thing.

It is actually a fun repair as long as you are taking your time and have a good fit up. The bevel is a key component for the strength and if the customer does it again it will break on the edge.

Fun fixes are on practice stuff. When a real repair shows up; things get serious.

Craig,
I hope us "ole" guys don't cause the youngen's to loose hope thinking they will be as old as us and still can't weld!!

The youngen's have stuff we never dreamed of. WAIT a MINUTE; you have stuff I never dreamed of. :P

In truth with the help of a newly aquired friend that is a retired boilermaker/pipe welder I am gaining confidence daily!

Cheater :P

funny yesterday I ran a bunch of SS and he said they would no problem pass cert test (great encouragent to say the least)

Congratulations, thumbs up smilie here.

I then did some Mig beads (on your 252) that I haven't found a suitable box to ship it in)

It doesn't need a box. Just put an address label on the handle to "Craig in Denver"; it'll get here. =-)

then ran a 1/8" fillet weld on AL and darned if it didn't look too bad!! (there is a God) and he held the torch today)

If'n you used that 252 fer an 1/8" fillet, did you use a spoolgun or run it thru the xx foot mig torch?? If'n you did, you have no use for that Dynasty. And it'll fit in a smaller box. :P

I will post a few progress photos as soon as I set up some "fresh coupons" Tim

Rubbin' it in, eh? =)

I did leave as much of the original structure, so I did not follow the recommendations to the letter. Mercury Performance wants you to cut down to the housing. I don't like that and feel it would guarantee a catastrophic failure if the lower unit was to be damaged again. My thinking is the machined part would rip the housing as to its material strength.
The weakest link being the casting, so you can follow my thought.

Thank you, hopefully I remembered this. :P

Craig, here is a coupon from many many years ago. It was a training piece I did when I finally felt I could do it. It reminds me of where I came from and the GOOD OLD DAYS PAST!
I gotta say, I was way to full of it then. How owning your own and growing up has it drawbacks...

Good luck, just be patient.

PATIENCE?!?! I don't have time for patience; I'm over 60!! It's funny to see someone else has evidence of their progression. A big part of classes is repetition; if I can't do it AGAIN, I'm not good enough!! You may have been full of it, but you didn't bring it here: thank you. Growing up sucks, waking up after my 60 something birthday; REALLY sucks. I suppose it's better than the alternative.

(Nice work btw) That is pretty much how I do it as well.
I never much cared to cut off the remaining skeg either.
I have repaired about as many poorly welded skegs as freshly damaged ones it seems sometimes. They seldom have 100% penetration and are always welded/spliced in a straight line.(

Keep it coming, I think I get smarter with everyone else's posts. =)

[Aerometalworker]

The mercury I had catch on fire was a verado five years ago. Motor had 500 some hours on it. It had an electrical short somewhere in the motor I suppose
did quite a bit of damage to the wiring harness and burnt the hood on the outboard up bad. As for the difference in the castings on the lowers of yamahas I have absolutely no idea what the specs are. i know there a great motors and very durable in my opinion. My regulator has 1500 hours on my four strokes with no problems.

Odd,
You must have had a 2005 model year engine, and since it was 5 years ago it was under warranty. So Mercury replaced it right? If so what was the warranty request number, engine serial number, or?? Id like to track it. I see a lot of times where people like to "bash" a brand, and make up false stories about them, unless you give me more information im assuming this is one of those cases.

FusionKing, you may know something about mercs....but im betting I know a bit more

[Aerometalworker]

Im guessing there was no fire, I cant find a record of a failure like that in the field EVER with a 6 cylinder Verado. Give me a serial number and prove me wrong, otherwise im calling your bluff.
-Aaron

P.S. welded skegs are never as strong as the original as you lose the heat treat in the aluminum from welding. Normally the welded on Skegs I find are not put on with the right geometry. Not too critical on a slow boat, but on something faster like a Bass boat it can really casue some dangerous handling issues. Ive got jigs to hold mine to the correct offset for each model.

[FusionKing]

FusionKing, you may know something about mercs....but im betting I know a bit more

I am sure you do Aaron I knew I would get you going with that statement.

welded skegs are never as strong as the original as you lose the heat treat in the aluminum from welding. Normally the welded on Skegs I find are not put on with the right geometry. Not too critical on a slow boat, but on something faster like a Bass boat it can really casue some dangerous handling issues. Ive got jigs to hold mine to the correct offset for each model.

I would really love to see some of that stuff (fixtures) I have done some that were a He!! of a lot faster than most bass boats!! I have thought a great deal about fixtures myself.
I would simply like to know what the correct offset is for differents models
I don't doubt one bit that there are better ways to weld these than I am doing. BUT...I do have a VERY steady steam of them coming to me on a regular basis and am very interested on any and all info to improve my methods

[Aerometalworker]

I am sure you do Aaron I knew I would get you going with that statement.



I would really love to see some of that stuff (fixtures) I have done some that were a He!! of a lot faster than most bass boats!! I have thought a great deal about fixtures myself.
I would simply like to know what the correct offset is for differents models
I don't doubt one bit that there are better ways to weld these than I am doing. BUT...I do have a VERY steady steam of them coming to me on a regular basis and am very interested on any and all info to improve my methods

FK,
he he yeah, if only I got fired up that easily. Really the only thing that bothers me is when people spread lies and stories about something I worked on, and they have little knowledge of. Hmmmm basicly my fixture holds the nose cone in a tapered cup, the prop shaft with a center. and an adjustable Vee block holds the drive shaft. The Alignment of the skeg is referenced from the imaginary line connecting the cup and center ( which are interchangeable to weld both sides after flipping the case ). Hmm I think we used to have a chart we gave to the repair shops that gave the offset in degrees, let me see if I can get an electronic version. You would probably get a kick out of our hydrodynamics testing with the high speed underwater cameras. I will also check and see if I can send a picture of the fixture, I dont see why not but since its engineering related I have to get approval.

[Ultrachop]

Craig,

You have darn near got me humbled enough to ship off the MM252 to you (I know the UPS guy pretty well and he has a tow hook on the back of his "brown truck" that I could half hitch the ground lead to and he could just tow it to Denver?? what ya think? By the way you have to be the best at "quote, paste", quote, paste" around!!

No I didn't Mig the AL coupon I actually ran two 7" tig fillets without screwing up to bad--Can't afford a spool gun and besides I haven't gotten a smoke evacuator for my little shop yet (wife and the Stock market have me on a short leash!)

FK and Aerometalworker, Both you guys are a great source of information and wisdom for us "ole" Newbie tig welders and I for one am truly humbled by the art form that you guys make of this process.

Tim (just slightly younger then Craig!)