Welding near stator - heat issue?

So I swapped my '93 20hp Mercury for a '96 20hp OMC. Everything was supposed to be fine but it turned out that the threads in the lower half of the block for starter bracket have been stripped, bored out, rethreaded and stripped again.

Bummer. It has to be welded/filled and bored out again.

I already dismantled everything flammable (carb, primer, hoses) and obviously heat-sensitive (intake manifold, reed cage, gaskets) nearby and now I'm preparing to weld. Or, more accurately, braze with Techno-Weld, which puts far less heat stress to cast aluminum parts like the block.

The only question mark is still the stator. It's approximately three inches from the stud.

I'll have to heat the stud/hole to approximately 720°F with a small butane torch to braze it. I'll lay it down on its back, intake side up so the heat won't raise to flywheel and stator. There will still be some heat conduction and the last thing I need at this point is frying the stator.

I'm 90% sure there won't be a problem, ignition parts are designed to withstand quite a bit of heat. They're also mostly detached from the block so there won't be substantial heat conduction, but the area to be brazed will still be pretty hot for a short period of time. It'll probably take less than three minutes to braze it.

I'd hate to have to pull the flywheel, I don't have tools at hand right now and will have to wait for tomorrow and drive some 60 miles to get a proper puller from home garage.

Braze it as-is? Yes or no? Educated guesses and experiences are welcome.

Check for opportunity to use a heli coil - I believe your working with aluminum so brazing I'm not aware as a fix . He'll coil seems my first thought . But I have not got much experience - it' slowing you down , I'm certain as with most broken fasteners or their base . Hopefully this prompts others to get involved and assist.

Do it right and yank the flywheel. If it damages it, you'll be yanking it anyway

Time serts work well and won't need to worry about heat

Thank you, gentlemen.

The situation is way past thread inserts. There's barely .1" of material left on a thin cast stud base on the right-hand side that takes the majority of the torque of the hefty starter. Thanks to whoever bored the oversize hole off-center. I'd love an easy solution but now it absolutely has to be welded.

I've had a number of OMC 31.8/521cc motors over the years and this one is getting the usual treatment. The largest 1.25" venturi carb, late model "tall" intake, reeds and the head will be shaved at least .045, maybe even .060". That'll make the starter work even harder against the increased compression so it really has to be fixed properly and stay put. I might even add material for strength, a bead or two on the outside of the bung.

Be it TIG I'd pull all electronics to avoid electrical damage but Techno-Weld means just a moderate heat load which might or might not be low enough for stator coil insulation to withstand. Other than that, there's not much to fry.

I may just pull the flywheel to make sure. Then again, fried coils are a great excuse to recoil the stator for a couple of more amps of charging power, something you never get around to do as long as it works... :D

Time sert also makes a Big Sert. Worth looking into. But they are not cheep.

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Originally Posted by hq_

Thank you, gentlemen.

The situation is way past thread inserts. There's barely .1" of material left on a thin cast stud base on the right-hand side that takes the majority of the torque of the hefty starter. Thanks to whoever bored the oversize hole off-center. I'd love an easy solution but now it absolutely has to be welded.

I've had a number of OMC 31.8/521cc motors over the years and this one is getting the usual treatment. The largest 1.25" venturi carb, late model "tall" intake, reeds and the head will be shaved at least .045, maybe even .060". That'll make the starter work even harder against the increased compression so it really has to be fixed properly and stay put. I might even add material for strength, a bead or two on the outside of the bung.

Be it TIG I'd pull all electronics to avoid electrical damage but Techno-Weld means just a moderate heat load which might or might not be low enough for stator coil insulation to withstand. Other than that, there's not much to fry.

I may just pull the flywheel to make sure. Then again, fried coils are a great excuse to recoil the stator for a couple of more amps of charging power, something you never get around to do as long as it works... :D

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Originally Posted by HStream1

Time sert also makes a Big Sert. Worth looking into. But they are not cheep.

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Thanks. However in this case they won't help because the whole bung lacks support on three sides and an insert of any kind will inevitably break off unless the whole piece is re-welded.

Good news is that I talked to a friend of mine, certified Mercury/Mercruiser mechanic with plenty of experience, and he has a TIG welder at his shop so I'll just let him handle it.

Problem solved. Now we'll have to wait and see if 40mph is going to happen with a 300lb aluminum V-hull fishing boat and a slightly tweaked Johnson.

Damn whoever the hell destroyed the thing should have their tools taken away.
Oh pics always help..
Well you've got someone to fix it so..
You don't need a starter bouncing around etc..
Always better to wait get what tools you need to do it right...look at what your having to fix ..he obviously didn't get the tools he needed and screwed that up..

https://www.timesert.com/

Wrap a damp rag around the crank snout . If it starts sizzling ( boiling water) it's time to stop .. at least till you can cool the surrounding area.
The right way of course would be to split the case , weld it up , flatten , drill and tap the hole on a mill .. unless "close" is good enough and you don't mind taking a chance of burning the seal up and the proof being the top cylinder that goes with it .. ;)

Hey , lean that drill to the left a little .. no, your other left .. OK , good ,, maybe down a little ..yup .. that'll work .. how come there's only threads on one side .. :cheers:

Chaz = thinkin, solder weld .. China make's open end wrench's out of that stuff .. :eek: :D

Charlie is that anything like smoke testin yer wiring harness:D

So pre heating that area is out of the question then ;). I mean a 200/250 deg pre heat and keep the interpasses no higher than 400 degs might be difficult. And a hand drill with a built in level wouldnt work?? HUM??? maybe a Drill guide on a flat hand filed surface thats not perpendicular with the Boss.

Quote:

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Originally Posted by Chaz

Wrap a damp rag around the crank snout . If it starts sizzling ( boiling water) it's time to stop .. at least till you can cool the surrounding area.
The right way of course would be to split the case , weld it up , flatten , drill and tap the hole on a mill .. unless "close" is good enough and you don't mind taking a chance of burning the seal up and the proof being the top cylinder that goes with it .. ;)

Hey , lean that drill to the left a little .. no, your other left .. OK , good ,, maybe down a little ..yup .. that'll work .. how come there's only threads on one side .. :cheers:

Chaz = thinkin, solder weld .. China make's open end wrench's out of that stuff .. :eek: :D

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Line it up and tig the bracket to the case forever

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Originally Posted by FMP

Line it up and tig the bracket to the case forever

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Otherwise, maybe, but this is not one of my ghetto engines and the bracket needs to be removed every time the reeds/intake/carb come off.

Quote:

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Originally Posted by Chaz

unless "close" is good enough

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Thanks for the tips. This time it is. It's a light duty lake motor for the kids and whatever works reliably will do. It would've been SO easy to repair unless the twat who "repaired" it last time had slipped around with a hand drill and overtorqued the new, larger bolt to boot.

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Originally Posted by TEXAS20225

Charlie is that anything like smoke testin yer wiring harness:D

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Tex , It's kinda the same … just a lil mo amperage .. :)

HQ , If you are gonna weld it from one side shape the hole like a funnel . If you can get at it from both sides , then make it look like an hourglass . Go to the (middle or bottom) close the hole and work your way up and out of the hole going around the circle. Lot less chance of finding an air picket when you shoot the hole .. :thumbsup:

Dead center drilling.. listen to what Uncle Bud said.. I'm just the stupid welder..:p:D

Transfer punch the hole thru the starter cap , make a "drill bushing" that fit's is the cap so you can drill it small , maybe one more step if there is a lot of wall material left . Final drill the hole to recommend size for tap . Keep the tap wet and send it thru .. I like to blow the chips out best I can before extracting the tap. My luck, I'll run over some chips on the way out .. and *&%$#^*& ^$#$8 the threads .. :o :)

Thanks again. It's a blind-end hole so funnel it is. Or whatever the mechanic buddy of mine chooses to do with TIG.

Techno-Weld resembles brazing and there's a nice oversize "cup" to fill so that might be easier and eliminate the risk of air pockets. I'll probably grab a couple of TW rods with me when I bring the motor and see what he thinks.

I should've been more careful inspecting the motor, it was absolutely filthy inside the cowling and more often than not that's a clear warning sign that something may be amiss. I'll probably install an auxiliary pull starter providing that I find a color-matched tall cowling, I only have Evinrude ones in various hues of blue right now. One of its three mounting screws goes to the electric starter bracket and reinforces the whole package even more.

FINALLY. The buddy of mine has been AWOL for several days so I went ahead with TechnoWeld. Not a chance. The rag on stator (flywheel is royally stuck, wouldn't budge with even a big puller) started boiling when the temperature of the boss was around 500°F and I didn't dare to heat it more.

So I experimented with a ghetto solution. I connected jumper cables to a truck battery, hooked one to a piece of scrap aluminum and another one to a TW rod. It arced and created a tough seam. To proof the concept, I welded two pieces of scrap aluminum together using this method and they held. I couldn't pull or even wiggle them apart with large tongs.

So here's the end result. I haven't sanded it all the way down yet but it seems more than solid enough to hold the starter.

Desperate times call for desperate measures...
Attachment 466287

I would think that "desperate times" would be out on the water in the middle of nowhere with the starter laying in the pan .. :eek:

Not in the shop planning the "best fix" to keep you out of the above situation .. :)

Don't worry, I wouldn't have left it as it is if I wasn't pretty sure it holds. It was considerably harder to grind than the aluminum in the block and not brittle at all so if something gives, it'll probably be the block itself.

Then again, it'll be used by my youngest (teenage) daughters who drive it 3 miles to get ice cream and go fishing on fair weather so if something goes wrong, it's hardly a disaster.

How did it feel when you drilled and tapped the hole ?

Little chips that sound brittle , long maluable curls , gummy .. ? Never used the stuff, just curious .. :cheers:

The power feed drills holes a lot better then me .. :o

.015 - .020 … err .3 -.5mm curl is what I aim for when drilling aluminum .. :)

Dad .. come get us .. :eek: Just kidding , I'm sure it's fine .. :thumbsup:

https://i.imgur.com/CcAHbrjl.jpg

https://i.imgur.com/wrbYzskl.jpg

No long curls, just chips with a fairly steady resistance. What surprised me was that a bargain basement "TiN" drill bit had hard time biting. Switched to cobalt for maximum overkill, drilled just fine. Threads cut nicely, though. I wouldn't compare it to a proper TIG weld but it certainly seems to be close enough for the purpose.

As far as reliability and emergency propulsion are concerned, I'll probably have to get the girls a better paddle. And make it look like their brother is at fault when something breaks down. :leaving:

I think they make those TIN bits from the slag when they make alum brazing rods ... :D

I bought a set of tungsten carbide at an estate sale. best bits I have ever owned .. :thumbsup:

It's bad enough for brother to live in the "hen house" .. but to get blamed for stuff he didn't do as well … :nonod: :D

The worst part is that their brother is an engineer so it's automatically his fault when anything that he has ever touched breaks down. Hence I've made sure he has given a hand in fixing the motor. The best part is that he lives in another town now and knows instinctively when not to answer the phone when either of his youngest sisters call.

It's going back together later this week anyway. I hope it works, a small tree fell on the aluminum boat it's going on and there's some semi-serious dent pulling to do before I get to install it.