bolt in jet ski intake grates and pumps

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semojetman

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Which model PWCs had the bolt in pumps where the intake and everything bolted in.

Looking for a good setup to put in a jetjon.
 
Yamaha XL1200, GP1200, I think the XL800 also. A few other PWC manufacturers, including Tigershark, made bolt-in ducts, but honestly, if you stick with the Yamaha, you can't go wrong.

That said, it looks like the few people I had interested in having a jet john built, have all backed out. So, here I sit with a VX110 motor, and before next summer, I'll likely build a class 1 rapids jetjohn, complete with UHMW. I'll be using the XL1200 pump for my build.
 
Sounds cool.

I was asking for a friend of mine.
He is building his out of a 1440 alumaweld and a sea doo xp.
I will let him know about the pumps.
 
Sea Doo and Yamaha use different type couplers. Easiest, and most durable method of engine-to-pump hookup like this, is to use a spartan jaw coupler. Simply modify the 2 halves of the coupler where they will thread onto the drive shaft and the engine.

Spartan jaw coupler eliminates all metal-to-metal wear, because of the rubber 'spider', and it also allows for vibration, deflection, and some mis-alignment (within .020")
 
I have yet to see if anyone has tried converting the 255 hp sea doo 4 tech to a jet Jon.... I wish I would have done more research first but I got a very nice 2008 sea doo rxt x with intentions on putting it in a 1656 mod v with an 8 degree dead rise. The biggest issue other than alignment of pump and motor is the fact that these skis have a closed loop cooling system. Coolant flows through the ride plate on the bottom of the ski. I do not plan on being in big rocks but in rocks none the less and I am worried I would put a hole in the ride plate and loose coolant! Could any of the more experienced jet Jon builders help with some ideas as to other options? I really want to use this power plant! Thanks in advance!
 
I had considered that but I know that the ride plate that holds the coolant is in direct contact with the water in order to cool. I just wonder if going over the ride plate with thick aluminum is going to keep it from cooling properly? Would a small 4 cylinder car radiator with electric fans be an option?
 
Does your pump have a water line output, perhaps for the exhaust?

You could rig a liquid/liquid heat exchanger.

Search for 'Silver Bullet' Jet Jon build, as he had a good idea on that.

Personally, I would just run it as is.

I ran over rocks this summer, left some scratches but no serious damage.
 
Adding another outlet on the thrust nozzle would give you the cooling water to run the on-board liquid/liquid heat exchanger. Although it is indeed a closed loop system for the engine, it still uses raw water and a total loss system for the exhaust manifold cooling. The line for the exhaust has to be used for that purpose or you'll cook your hoses without it.
 
ya the ski is not fully closed loop a lot of guys seek to convert it to conventional open loop system.
 
Thanks guys for all of your input! Is there any other reason I haven't seen anyone using this engine for a jet Jon? Seems like it would give good power in a boat?
 
Yep, what amk said. $$$$

Most people that build a jet john the first time out aren't into spending a lot of money to get a running boat. They may spend the money on fabricating decking or other structures, and everything else that building a boat entails, but most people are looking for a relatively inexpensive, lightweight engine with moderate power.

When I built my boat, I used a 600 dollar Tigershark engine, because, for one thing, I wasn't sure if my idea was even going to work, or how it might perform. But after having had the boat and run it for a while, I was convinced it needed a more powerful and reliable engine, especially with all the problems it was continuing to have with blowing holes in the pistons.

So, I bit the bullet, and spent 2500 dollars on a Yamaha MR-1 that I got for a really good deal, considering the low hours. It was a lot of work to re-configure my engine compartment for the new engine, but in the end, it all worked out great, and I just wish I'd done it this way to begin with!
 

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