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Jet Ski - Explained

705 ratings | 158047 views
How do jet skis work? What propels a personal watercraft? The basic concepts involved on how a personal watercraft is propelled and how the components involved work. Please feel free to rate, comment, and subscribe! And don't forget to check out my Facebook page: http://www.facebook.com/engineeringexplained Also check out my official website: Make suggestions, participate in forums, enter for Car of the Month, learn through logically ordered lessons, read FAQs, and plan your future! http://www.howdoesacarwork.com NEW VIDEOS EVERY WEDNESDAY!
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Text Comments (99)
Ivan Lopez (1 month ago)
there is a boob..
tim mumba (2 months ago)
Were is the intake on it
dXb (1 month ago)
Behind the engine. Are you blind?
Tegan Burns (2 months ago)
Thank you!
boobie bars
Peter (3 months ago)
I preferred these older videos than the new ones that u do tbh
Thank's bra 100% like it
Chris L (4 months ago)
well done
Michael Contreras (4 months ago)
so is jetski gonna intake a little bit of water near the driveshaft while in water
Michael Contreras (4 months ago)
I can’t take it the drive shaft off cause plastic is coving it has harden and I can’t get it out
Michael Contreras (4 months ago)
Okay so my jet ski is intaking water near the drive shaft so what do I do
Keith Payne (4 months ago)
No it is sealed off
Michael Contreras (4 months ago)
someone please answer w/ the right answer
scallen2112 (5 months ago)
You forgot to label the asshole on top of it.
A W (6 months ago)
You are awesome. Thanks!
J Bakes (7 months ago)
Nothing to see here folks, just Newtons third law in action.
Kevin V (10 months ago)
Your handle bar looks like a boob.
Philly Cheese Take (1 month ago)
It's the next generation of jet-ski design. In the place of cylindrical handlebars, are a pair of realistic rubber tits. Give them a few good slaps to start the engine, push them together to move forward, thumbing the nipples to control direction. To reverse, grip both nipples and pull backwards. To switch the engine off, plant your face between them and shake your head.
Inboundbogie (3 months ago)
I thought I was the only one who thought that too hahaha.
mrpowdercoater (3 months ago)
Kevin V You're just a horny little....no wait.....yeah, yeah it does.
Emmet Moore (1 year ago)
Love the old videos you've come far!
Abhilash Patel (1 year ago)
I bow to you. Such a nice explanation within 2 minutes. :) Now, could you explain flyboard, please? I am dying to know about it.
Dan Ivanov (1 year ago)
how does reverse function with the plate if the water is getting sucked in the opposite direction? shouldn't there be another plate in the intake? Or is it good enough
Dan Ivanov (1 year ago)
gotcha, thanks
nikita kvasnitskiy (1 year ago)
Dan Ivanov theirs a bucket that redirects it under
Shaine MacDonald (1 year ago)
Do you have an personal watercraft videos that go into more detail?
Alex Johnson (1 year ago)
What do you think the peak efficiency of the impeller is? (assuming the engine is operating at perfect efficiency)
Rodrigo Monteiro (1 year ago)
Some jet skis have systems that prevent them to capsize. How do they work? Thanks!
Ricardo Iglesias (2 years ago)
you should revisit this one since youve come a long way since
Jimmy Danger Gonzalez (2 years ago)
I didn't know jet skis had boobs on them... I love your videos! Just had to razz you on the handlebar boob!
Plasma Owl (2 years ago)
So cool
zeetweets_ (2 years ago)
17 scumbags
cardayz (2 years ago)
How can an engine work without air supple if it requires air for combustion. I only know about car engines and how the more air inside the cylinder, the more effective the engine. So wouldn't this make the engine extremely inefficient
Richard Smout (6 months ago)
This is why I'm watching this video
RealationGames (2 years ago)
I think you are mixing jet skis with submarines...
3DPeter (2 years ago)
+cardayz A jetski always has some openings under the seat or on the bonnit for letting air in the engine compartment, and when some water does get in the compartment, a small waterpump wil pump it away, so it's simple as that.
Alex Varela (3 years ago)
can you take this motor and mount it in a go kart or you have to consider the heat
Akash Nigam (3 years ago)
what kind of joint allows the driveshaft to change direction and provide torque at the same time
Bruce Wizayne (2 years ago)
+Akash Nigam watch it again. has nothing to do about changing direction. still keeps moving the same direction just the force creating the thrust out the nozzle is redirected at an angle down and under the craft. thus changing the direction of the "pushing" forces that move the craft
Vasco Cruz (3 years ago)
Thanks :D 
Mohamad Simo (3 years ago)
Amazing description thanks a lot 
night. (3 years ago)
how can i calculate the impeller force and water resistance and is the water resistance vary with speed ?
VarunKatwaroo (3 years ago)
So how do you accelerate the Jet Ski, if there isn't a transmission to adjust the amount of power being sent to the propellor by the engine? 
Laumola96 (2 years ago)
If you didn't understand how the power were adjusted, I'm pretty sure your new jet ski will be a dream only. You clearly know way too little to be able to even remotely build something like that. Sorry!
VarunKatwaroo (3 years ago)
Thanks Man :) I'm a Mechanical Engineering BSc. student and inventor by hobby, i'm working on a new type of jet-ski , and i'm currently in the process of analysing the characteristics of normal jet-ski's and stumbled on your video :)
Engineering Explained (3 years ago)
+Cobrastarzz1 By modulating the throttle. Full throttle = full acceleration.
OfficialAfflection (4 years ago)
Hi there, if i would suck in gravel in the impellar, would it have any negative effects on the engine?
goochii67 (4 years ago)
Great video! So jet skis are air cooled, and not water cooled?
1greghawk (3 years ago)
no ...theyre  salt water cooled, yamaha use intaken salt water to cool, seadoo use a closed loop cooling like a car radiator
Beach Life (4 years ago)
i just got my first pwc and someone on a messageboard suggested i see your vid. thanks so much!
John Knoxville (4 years ago)
Bro. You're so good in explaining about motors. Thanks.
Engineering Explained (4 years ago)
Thanks for watching!
Amber Restad (4 years ago)
Hey, this was really great! My students asked me how a jetski worked and I showed them this video. It made perfect sense. They really enjoyed it.
Engineering Explained (4 years ago)
Awesome! Thanks for sharing!
Slim Charles (5 years ago)
Nice video and nicely explained. Thanks.
71502 (5 years ago)
make sense, which one do u think it better? The impeller will be good in seaweed or stumps areas but will it decrease the performance because it's basically a "enclosed" propeller?
Russell Saputo (5 years ago)
im not sure but jetskis and waverunners do not use that design.
Engineering Explained (5 years ago)
It's simply a shaft driven impeller, rather than a shaft driven propeller.
71502 (5 years ago)
Sorry for my typo in my previous statement, what I meant is what do you call those engines. The engine that sucks in water and shoots it out to propel the watercraft forward instead of using the propeller?
hichhichh (5 years ago)
Thanks for the awesome explanation. I always wondered how jetski's worked.
DI5PICABLE (5 years ago)
Can you make a video on explaining wheel offset
alopez4472 (5 years ago)
Looks like someone wants a jet ski haha jk keep up the good work!!! You've taught me a lot!
Engineering Explained (5 years ago)
Nope, Rotax makes 2-stroke and 4-stroke piston-cylinder engines.
Mark Cotner (5 years ago)
You mention piston/cylinder at the beginning, but I was under the impression most(Seadoo) are rotax. Aren't rotax rotary?
Russell Saputo (5 years ago)
the water is sucked into the intake grate on the bottom and is sucked into the propeller which shoots it out the nozzle
71502 (5 years ago)
so what do you can those engine that sucks in water and shoots it out instead of the ones with the water propellers?
Russell Saputo (5 years ago)
you could ask the same thing about cars, planes, or any other invention
Russell Saputo (5 years ago)
all jet skis and waverunners use propellers
Russell Saputo (5 years ago)
correct but the impeller propels the water out of the nozzle but yes you are correct
Indra Ida Bagus (5 years ago)
Isn't a jet ski impeller above (a bit above) water surface (I just look where is the nozzle to estimate where is the impeller =P)?
Indra Ida Bagus (5 years ago)
But it use water to drive rather than the prop blade itself to drive the vehicle.
jhoff (5 years ago)
Regular prop engines also force the craft to "plane off" more which in such a small craft at such high speeds you'd probably lose a lot of the control that you have with a jet.
Elite_NoFksGivn (5 years ago)
How much free time would someone have to invent a jetski..
Engineering Explained (5 years ago)
Friction, actually. Water under the boat can actually stop it pretty quickly. Some newer ones do include water brakes where you stick a plate out to slow down the boat.
Gopro Master (1 year ago)
Well a bucket but same thing
Alpha Wolf (5 years ago)
How does it stop?
Russell Saputo (5 years ago)
the impeller works like a regular prop
Erick Olivares (5 years ago)
P Hennessy (5 years ago)
The housed impeller was developed by Hamilton jet. Allows jet skis/ boats in low level water without having your prop hit rocks etc. wikipedia. org/wiki/Jetboat
Vega Motor Werkz (5 years ago)
I know exactly what kind of handles you were thinking of when you drew that lol
Engineering Explained (5 years ago)
Probably safety reasons of not having a prop. People fall off jetskis more frequently, you don't want to fall back onto a prop.
yardman0001 (5 years ago)
Why not just make it like a regular boat or ship with a prop instead of a stream of water?
Engineering Explained (5 years ago)
Yes, they still have a transmission. A lot of scooters use CVTs though, so no changing gears. I've got a video on CVTs if you're interested.
TupacW (5 years ago)
so a scooter doesn't either have a transmission? since you cant reverse, or is it automatic?
Engineering Explained (5 years ago)
The intake is within the jetski, could be up near the front - air will be drawn in from the top of the jetski. The engine compartment is sealed.
xod (5 years ago)
where is the intake and what did the engineers do to prevent (too much) water from reaching the combustion chamber?
InSearchOfReality (5 years ago)
Or it could be the water used to cool the engine like an outboard motor?
71502 (5 years ago)
so is this type of design consider propeller engine that uses propeller to move forward or engine that uses water the move forward? Doesn't know what that type of engine is called..
vincent sit (5 years ago)
then where does the "rooster tail" come from? or what role does it play in driving the jet ski forward?
Engineering Explained (5 years ago)
It is, I've just drawn it a little funky.
71502 (5 years ago)
so the impeller or the propeller of a jet ski is not under the water surface??
MrShriepshroepshrap (5 years ago)
Michael P. (6 years ago)
Awesome video. I've been wondering this for awhile..lol
Mix Bag (6 years ago)
ok so i want my exhaust loud.but because its under water its not very loud. would it be ok if i put the exhaust exit hole above the water line.. that way i would have louder sound....would this be safe to do for engine.... i have a 2stroke 50hp
Engineering Explained (6 years ago)
Haha for kicks. There is no function to it as far as I know, just a flap creating more drag to put a stream into the air for looks.
Tyler Pirkle (6 years ago)
very nice man
Robert Witkowski (6 years ago)
thank you! very informational!
Devang R Gohil (6 years ago)
good explination Bro!!!
farshidmt (7 years ago)
great video

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