I’d make a rubber bladder to line the gas tank. That way any small hole in a weld or crack in the hull won’t mix fuel and water or leak fuel.

I recommend throwing a bladder inside that tank. If one little thing makes a tiny hole, its all over. A fuel bladder would give you and the water outside of you a mile of security. I absolutely love how this is coming together though. Great work guys, its awesome. Edit: of course with a bladder, the need for an in-bladder feed and return arises. Tackle that how you will with the tank being the actual boat, it's still a massive amount of security for everything involved and in my opinion, well worth the extra work. If you have another solution im not thinking of though, fantastic.

I'd highly recommend re-visiting the fuel tank. aluminum is strong, but big ass rocks are stronger. Maybe a slim, tall, and long fuel tank down the side of the boat? Even 3.5" wide to fit up under the gunwales would work. Or one that lays in the floor following the contour of the stringers. The point is, a double wall design is NEEDED. If you dump a full tank in the water your gonna hear about it!

Ooooo risky move with the gas tank. Based on how Cleeter ripped his hull a couple of times already, not sure. Gotta watch out for the nose.

A bladder tank would have been a good idea to put inside of the tank. At least it would be another layer of protection.

One of the reasons I watch this channel is Ethan's recycling program. I get that it's because you live in the stix, but it's inspirational to see how far you go and what you make out of the scraps of other builds.

The pipe you got is a good one, you’ll get a good 15hp increase over stock. You could easily make a custom water box. They are very simple in design. They serve 2 purposes, noise reduction and reducing the ability for water to back flow into the engine in the event the boat capsizes. Cut open the one that came with the ski to see what it looks like inside. It’s a little different than a car muffler. You can further quiet the boat down if you need to by adding cooling lines and running water directly to the water box to help spray additional water into it. It might be a good idea to mount the ebox to a wall to reduce the chance of it getting water inside. I would remove the oil tank and the oil pump from the front of the engine and run premixed fuel at 40:1 (as long as you’re confident in the front tank not leaking or sustaining damage). The oil pumps can fail. Just make a small block off plate for the front. Also, remove the crank case drain and make a block off plate for that (you can see a pics of these online for ideas). I spend most my free time tinkering with these engines & skis. These tips have worked well for me and are very common mods.

SOUNDS INSANE!

Gas tank concerns: These aluminum jet boats are fun and fast. Denting and fixing them is a very regular occurrence. For the gas tank design to be safe it would need a flexible fuel bladder. Just like what f1 uses. That way the gas tank can deform on a rock while keeping the fuel safe in a puncture proof pouch. Love the build!

Ehhhh not the best idea on the gas tank. One stick, rock or anything to put a micro hole in the hull and you have just contaminated your entire fuel tank leaving you stranded. Better put a large fuel/water separator and not send it to hard. Think your original idea of a separate tank mounted up inside was a better idea and would have kept the fuel safe from contamination.

What you need is a fuel cell for your gas tank. As a retired welder with over 60 years experience I can guarantee that your bulkhead will develop stress cracks almost immediately when running this boat. Then you'll be sitting in gasoline or you'll be surrounded by flames. It's your choice. Sometimes the quick and easy way is the worst way. Just my opinion.

Awesome build, love your stuff. I like the feature of the driver being presoaked in fuel before the ignition by the engine for extra crispness lol.

You should consider using some of that fiberglass wrap for the exhaust. It makes a pretty big difference for keeping things running cool and creature comfort. Plus it looks sick

Ethan: "I'm out of TIG rod" Lathe: "Say no more"

Some of the most insanely resourceful work I have ever seen and your designin engineering is off of the charts, I wish I had a 10th of your skills! Keep up the killer content and as usual I'll be looking forward for the next one.

Put the explosive liquid at the crashy end .. true GHP engineering 😅😅 it ain't fun if it ain't dangerous 👍👍

You guys are super inspiring, greetings from norway 🇳🇴🇳🇴

As a boat builder that's not the idea I'd go with for the fuel tank, but I would definitely go with a sealed cap vs that vent cap.

I so enjoy watching you work at your age I was the working on diesel engines and never had the money or time to do what you guys are doing I would love to relive that time. love you ideas

I'm gonna parrot everyone else on here and say: having the hull have a double function as a gas tank isn't the best idea. At the very least, you should put a fuel bladder in there in case of any leaks.

There's a certain office building in town i hate. Their driveway to the parking lot floods a lot when it rains hard, they even put on "waterproof" extra front doors. It's super great lot/building design, nowhere near water, they built *below* road grade for their entrance 😂. I want one of these to rip around in their puddle, it's plenty deep and big enough.

I love watching you work and the pure talent you have to just freehand anything

How awesome! Making the front of the boat into a gas tank, using parts of another gas tank, and welded together with filler rod made of gas tank lol.

Super excited about this build. It’s a first for y’all and I’ve seen the other builds which are absolutely wild. Keep up the hard work💪

Can’t wait til you guys get it on the water! My son wants to build one now, we would probably just go with a js300 engine. He doesn’t need that much power. Keep up the good work.

The idea of making a tank like this seems good, but what about if you hit something and it punctures the tank?

Instead of having a generic gas cap, you should cast some sort of hood ornament similar to the spirit of ecstacy. Probably could do it with lost pla 3d print casting.

Before you send that thing through a swamp, consider putting a thick plastic sheet on the hull as a protector. Think screen protector for your phone. If not a sticker, then maybe a layer of epoxy.

Yeah water boxes are pretty important the water that through acts like an extra amount of back pressure that cools the exhaust that helps the motor run cooler every waterblock has a special designed to prevent water from going back up into the engine too

The oil injection system is not entirely good. I’d recommend you get the block off plates for the oil injection system. And just premix from personal experience with my x-2.

Atlas lathes are known for getting grooves in the ways especially if they are never cleaned. The chips get under the wipers and act like sandpaper.

It never gets old seeing how long of a chip you can make

Oh this will be one of the most awesome things you guys have built!

Building the gas tank into the boat was genius! Can’t wait to see the first test rip!👌👍

Super sweet! Can’t wait to see it in the water.

i love the way you explain everything and you don’t even pause to think it just comes out perfectly.

I was actually thinking about using the hull for the gas tank but my only concern is leaks if you dent the front. Also I'm wondering how bad low speed stability will be with weight bias forward as it looks to be. I guess we will see 👀

Glad to see people actually putting a muffler on their crazy projects for once. You only get one set of ears

The moment I’ve been waiting for since the announcement of the project!

You are one of a handful of genius craftsmen on KZfaq. Truly mesmerizing.

😃 *This is the video I've been waiting for.. It's more fun to watch the process than it ends 👌* 22:10 *BTW, the BMW exhaust is produced in my country (INDONESIA) to be precise in the Purbalingga area (almost one sub-district of exhaust artist craftsmen).*

Bit risky having a single skin tank in the cockpit of the boat given the abuse JetBoats tend to get, Not watched all the video but I hope to god to include a lot more protection than the single skin hull.

I love how you can operate the lathe. Not many people know how to use those old machines anymore cause it’s all by computer now. I tip my hat to you sir!

That mystery exhaust part is called a head pipe, i love that you guys are doing jet ski stuff. Where some of the baddest 2 strokes are hiding

Ethan is so proficient at fabricating, that he can make even the most basic of parts faster than a trip to the hardware store. "Why take a trip and buy 10 screws when I only need one? I'll just make it real quick." Wild.

The sound when it first started was awesome

I sure hope one day you get to collab with ole cleeter, would be such a blast. This boat is going to be ROWDY!!!

Line the bottom of the boat with 5/16" or 1/4" Delrin sheet. It will make it slide over rocks an logs and protect the bottom of the boat from holes including your gas tank. It will really bullet proof your set up and it's pretty light.

Definitely once you and boosted boys have theirs done. We the audience need a collab between you, boosted boys, and cleetus mcfarland taking the jet boats out to some narly rivers!

This is quickly become my favorite project

Yall are awesome fr! Watching these crazy builds gets me so inspired to do stuff myself, u guys have gotten so much better at everything and learnt a lot from experience, PLEASE keep on doing this stuff, it really brightens up many ppl's day. Love from Sweden

I completely forgot it was Friday going hard plumbing day hope you guys are having an excellent Friday and hope you have a great weekend

That little ripper is going to be the most terrifyingly awesome thing in the water!

Ethan's new tshirt idea! "If only I'd brought a crescent wrench." 👕

I liked the sound of the engine at high revs at the beginning of the video. Very expensive high-quality exhaust sound👍

The reason I like this show is how good yall utilize the welder. If it doesn't fit, cut it an weld it so it does. Nice reuse of millings too

I’m pumped about this whole build! I want a mini jet boat so bad haha Definitely put a bladder in that tank though!

Awesome video guys! I can't wait to see this thing rip around on the water!!

My first discovery of your channel! Excellent! Got me now.

its cool that when you weld the cap stem on you can see the metal changing with temperature during the time laps.

Make the exhaust into a flagpole straight up from the middle of the back of the boat, with a skull cap so the smoke comes out the eyes and mouth.

Very cool. That stainless exhaust looks and sounds awesome

I’m so stoked! I can’t wait to see that rip.

For the exhaust option i can help on that! don't use the catalytic converter since it will heat up like crazy and create allot of back pressure! it will easily clog since it's a 2Stroke! What i suggest is running the exhaust under the rear deck and in the water with a proper Water Box With a pipe arrangement to lock water also called WaterLock! that will not only muffle the sound but it's also the proper marine equipment! if you want this jetboat to be reliable and proper i suggest doing those before ending the build! Other than that i enjoy the build allot! you guys rock on machining and creating! I've been watching since you guy's announced the jetboat build

Super cool project. Constructive input: I would have pressurized the cell with air and sprayed soapy water to inspect for leaks instead of having to contaminate the cell with water. And I would make sure to add some one way vents ( oem seadoo vents are good for 1.5) to allow for air displacement in the cell

I like how they look at other utube channels and use there ideas to this channel hell yeah brother

How have I never notice Ethan's hand tat thats awesome I love it

Dude fabricated two perfect fittings for the fuel lines himself. This dude is insanely talented

Looking and sounding stellar!

Yeeeees finally! You guys are awesome, wish I could do the same and having my own little shop. All the love from Sweden 🇸🇪💙💛

17:17 wheelie bar on the barbie camper looks sick

I have a 750sx set up as limited ski for racing. Limited do not require a waterbox. it's just louder. Performance does not decrease it increases. Dump the oil injection because the only way to tell when the pump dies is a seized engine.

100 percent agree. The original idea tacked in with a couple of inches of room around the tank would be ideal. Awesome build though guys keep em coming!

I am very excited with this build, keep on going!

Sounds like perfect second channel name for you guys "Grind Hard Recycling Co".

Same motor in my 750sts. Awesome motor. I love my older ski. Super reliable motor. It just works.

I would love to see someone go surprise theses guys wit 1 of those pre fabbed pole barns aka a nice size new shop I think that would be amazing

its like a go kart version of a jet boat ..this thing would be so fun to ride...i want one ..

Ethan is so cool I wish I had a friend like Ethan.😢

I cant wait to see the over the top trailer they make for the boat

Off to the spinny spinny thing👍🤣. I use to work for a company that made eletric scooters chairs for the elderly. I know it takes alot of work to do all that. Love the videos.

A couple of things with this build.. which I love! speaking from experience you’re going to need trim tabs. Also I’m betting with that short of a jet intake you’re going to have cavitation. Best luck can’t wait to see the end result.

Id love to see a collaboration with Cleetus McFarland an his jet boats!!!!

Dude, you have made skills that I wish I had. Can't wait to see that thing run.

You should bring that to the Clackamas River in Oregon when it's finished. We invented the sport of shooting the rapids going upstream. No exaggeration. Bring it.

Sounds so good without the muffler

Hey guys, if you guys can find a new trim box, you could put trim tabs on the back of the boat to get it plane out faster. Just a thought. Awesome work. ;-)

Love this build its going to be so sick ones it's running full throttle

When I seen this video about the jet boat. I got SO EXCITED 😆🙏😁

You guys should take your boat and play with Cletus McFarland and theirs. I'd love to see you guys rip it up together

New achievement: Brazilian Welding - Use whatever you have at hand as welding wire. Btw the gas cap on my car was welded on with barbed wire.

You guys are mad talented

I love seeing the electric die grinder, after watching the video with donut! I gotta say, I could also use one. Great video!

Nice work guys. Remember to order a metal deburring scraper. 😉

This is a great build and your videos are great, but, please secure this gas-tank more. What if you hit a rock or something, contaminating a whole lake.. I'm sure you have a good idea to fix it! Thanks for the video

Cool gas tank! Great idea adding a puncture resistant bladder inside that bulkhead!

Been waiting on a update!! How you guys approach problems. Is genius 👏 and the way you guys talk to eachother is amazing. You can genuinely tell these guys are real! Love the videos boys !! Keep it up

As an Engineer I love the CAD shirt, and I actually just got mine yesterday!

I bet these guys made some AWESOME bongs back in high school. Would've put my soda bottle and pen cap to shame.

This is magical . Love it