# bolt in jet ski intake grates and pumps



## semojetman (Nov 15, 2013)

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.


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## PSG-1 (Nov 15, 2013)

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.


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## semojetman (Nov 15, 2013)

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.


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## PSG-1 (Nov 15, 2013)

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")


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## Bpilgreen (Oct 24, 2015)

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!


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## CedarRiverScooter (Oct 25, 2015)

Could you weld an extra thickness of aluminum to the ride plate?


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## Bpilgreen (Oct 25, 2015)

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?


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## CedarRiverScooter (Oct 25, 2015)

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.


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## PSG-1 (Oct 26, 2015)

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.


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## amk (Oct 26, 2015)

ya the ski is not fully closed loop a lot of guys seek to convert it to conventional open loop system.


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## Bpilgreen (Oct 26, 2015)

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?


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## amk (Oct 26, 2015)

$$$$$


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## PSG-1 (Oct 26, 2015)

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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