Yamaha 784cc into welded mod-v hull


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Well today I managed to improve the setup of the welder. Quick recap, I'm using a Lincoln Weldpak 180HD which is the same 220v unit you'd find at Home Depot and others. It has stepped voltage settings instead of the continuous settings of the premium weldpak 180. I'm using a generic blue ptfe liner, and pushing 5356 wire from the unit itself instead of a spool gun.

I managed to find some .035" wire and some .045" contact tips. I also refreshed the gun with a new diffuser and nozzle. Not Lincoln brand, but generic tweco-compatible consumable bits from a random online supplier. Next I carefully straightened the neck portion of the gun a bit. It was clearly past the 45deg angle, and with it closer to 40deg I figure it would feed more smoothly. I brushed clean the feed rollers, and completely loosened the drive roll setting and the spool holder tension. After dialing in the wire speed and voltage settings, the sporatic feed problems I was having with the .030" wire are completely gone. I haven't had a single birdsnest for this entire pound of wire. Now that I've said that, I probably have jinxed myself. The roller feed tension is as light as possible, and the wire will slip in the drive rolls if the wire burns back and sticks in the contact tip. Argon flow is increased from 19cfh to 25cfh.

Also, at the suggestion from my mentor, I've tried getting some gas pre-flow to shield the arc before it strikes. The machine isn't set up for it, but with the wire trimmed right back to the tip, and then blipping the trigger once before holding it I can get a burp of gas to the weld site. This, along with the slightly increased flow setting has greatly improved the consistancy of my welds without a spool gun.

So why not just get a spool gun? It's because I want greater access to tight areas and corners. And it's bulky. And the additional cost of course. And I'm stubborn and want to do it the hard way sometimes. But now it works fine! I went down this whole path because my mentor, who has since moved away, used to do tons of aluminum welding with a similar setup. They just pushed wire through the whip. So if you're trying to weld without a spool gun, don't give up! It's possible, but the learning curve is somewhat steep and frustrating.

Cheers, B
Great story on getting it to feed alum wire.

I used my antique miller to weld alum through the cable & more wire went in the trash than into a weld. But I was too stubborn to buy a better welder. There is no spool gun available for a 50 yo millermatic.

Keep up the good work & the pictures.
Well the shaft finally arrived in Ontario after 5 week hiatus. Apparently the Post Office in Missisauga was shut down several times. But it was delivered. Three weeks later the machine shop had cut and resplined my shaft, and sent back both pieces via courier, and they arrived in 3 days. Yay!


I am well pleased with the work, and the price, and the speed of return shipping. Quick shout out to MINIJET.inc for speedy service with great communication at an excellent price.

Now with the shaft back, I get to re-assemble the coupler and the jet pump. Half way through, I'm looking at the parts, and I don't know where the two black washers fit. The big one is a spacer, but the little one? No clue. The repair manual has no photos, so I simply pressed the bearings and shaft back together into the stator housing. I put the spacer in, and decided the small rubber washer must fit in behind the impeller.



After dinner, I decided to use the power of the internet to figure out where everything fits. And I found this excellent writeup with photos of where all the pieces go.


After reading that, I find that the rubber washer doesn't belong. Not sure where it goes, but it defintely needs to be removed. So I'll take the impeller back off tomorrow. If it's stuck, I'll have to take the pump to the boat shop to use their spline tool again.

Well, while I was figuring out the pump, I decided to remove the fuel tank from my front cut. So I siphoned out the gas into a jerrycan to pour into my truck's auxiliary fuel tank. This way it's safely stored, and can be mixed in with fresh gas at any ratio I choose. I drained about 12 gallons out of the tank, and the gas is about 2.5y old and smells like paint thinner. It was 94 octane ethanol free, but now smells more like 74 octane. I hope the truck doesn't run too rough when I blend in the old gas.


Years ago, when I first started working on this ski, I dropped an 8mm socket into the abyss when loosening one of the many hose clamps on the engine. After fishing around for half an hour, I decided I needed a pair of wrenches to deal with all the hose clamps. I've always liked Facom tools, so spent quite a few bucks on three of them. 1/4", 7mm, and 8mm sizes. These wrenches are one piece so the socket can't fall off, are compact so they reach clamps in tight spaces, and the other end gives tremendous leverage, way more than needed to loosen even the tightest hose clamp. Highly recommended. Money well spent. If additional leverage is needed, a small screwdriver or allen key can be slid through the short leg to get leverage and reach.


With the tank drained and removed, I could toss it into the nose of the boat to see if it fit under the proposed deck. Yay, will fit, and there's lots of clearance for reinforcement ribs on the nose of the hull as well. Only issue is that the filler neck is on the opposite side of the truck, so it will be inconvenient to fill both at the same time. Also, the filler neck hose isn't quite long enough to reach to the gunwale, so I'll need to figure out whether I want the original Yamaha filler cap or not. And since the cap is missing a chunk, I may elect to use a standard filler neck.


The cockpit sole has been prepared for plug welding to the longitudinals. 102 holes drilled, deburred on the bottom, and heavily chamfered on the top. Waiting for buddy to find time to come over and TIG all the watertight seams and spots.


See you on the water,


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