# new build



## Imgoodatwhatido (Nov 24, 2012)

Well i decided to sell my little 14 foot jet jon and build something bigger. Got it sold and now ive bought a 1652 sea ark. My girlfriends cousin had a 2004 yamaha 1200xlt 155 hp ski settin around that wouldnt run. I checked all the cylinders and it had good compression and ended up givin $1000 for it. Put a new CDI box in it an now it runs like a scalded dog. I put it on the duck river yesterday and its a BEAST. It runs about 62 mph. So heres the next build. Ill try to keep pics posted as its goin on. any input from yall would be great.


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## PSG-1 (Nov 24, 2012)

I'm thinking that model ski uses a bolt-in aluminum duct, not molded into the hull like most. If so, then you'll be able to do your build in a manner similar to my Aluma-Jet.

If the tunnel is molded into the hull, you'll have to do the cut-and-splice method, which is what most people do.

Either one works, but I like the bolt-in tunnel, as it can be replaced if it were ever damaged, the new factory tunnel bolts up without modification, unlike trying to splice in a new fiberglass tunnel.

Take a look at my boat for some ideas, and let me know if you have any questions, as I have done this not once, but twice, so, I'm pretty familiar with the idiosyncrasies involved.


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## Imgoodatwhatido (Nov 25, 2012)

Unfortunately this ski has the molded intake. Pretty much all of them after 2000 have the molded intake. Im gonna try to find a entire pump assembly from a 97-99 gp1200. Its the bolt in style and makes things a lot easier as I found out on my last build. I'm shooting for 45 mph outta this boat. With 155 horse at the pump i think it will manage. I like your aluma jet thats a nice ride.


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## PSG-1 (Nov 25, 2012)

Imgoodatwhatido said:


> Unfortunately this ski has the molded intake. Pretty much all of them after 2000 have the molded intake. Im gonna try to find a entire pump assembly from a 97-99 gp1200. Its the bolt in style and makes things a lot easier as I found out on my last build. I'm shooting for 45 mph outta this boat. With 155 horse at the pump i think it will manage. I like your aluma jet thats a nice ride.



Thanks! I had a lot of fun building my boat, and even more fun taking it places I never thought I could take a boat. It's been everywhere from Cherry Grove to Cape Romain, and as far west as Cheraw, all the way up to the fall line of the Pee Dee River.

As for your build, you should get 45 MPH out of it. My MR-1 engine is 160 HP, and that's about what I get for top end. You can always experiment with different impellers. Also, you may gain a MPH or two by installing a "Wet Wolf Adjust-A-Thrust" cone on your pump. It uses a spring loaded shuttle, which is controlled by pump speed and pressure. In addition to slightly constricting the pump's bore at high speed, resulting in more top end, this slight restriction also helps with pump hook-up in choppy water, eliminating some of the cavitation of the Yamaha 155mm pump, which is what your ski uses.

As far as the bolt-in pump vs a molded in pump, since you've also already been there and done it, then you know exactly what I'm talking about! This should be a pretty easy build for ya. :mrgreen:

My boat is using a 1998 XL1200 pump, with a +5 degree exit nozzle, and the +5 degree wet wolf cone. But any Yamaha pump that uses the bolt-in tunnel like this is going to be the same.

To me, the worst part of installing that pump tunnel, is fabricating the wedge-shape toward the front end of where the pump meets the boat, as the body of the pump starts about 1/2" thick at its rear end, and then tapers to 1/16" at its forward end. 

Trying to make a wedge shape in the hull of the boat to match this was a real bastard!! A LOT of cussing, and grinding! After doing it the first time, I learned that this is the FIRST thing you do to the boat, go ahead and lay everything out, and install the pump, while the boat is upside down, it makes the job go MUCH easier!


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## Imgoodatwhatido (Nov 25, 2012)

ill keep that in mind thanks for the advice!

after lookin at your build, did you shorten the impeller shaft on the pump?

yours is a pretty good comparison as to what kinda speed i should get. This engine already has the d plate in the exhaust and the cat removed with a sensor block off. Stock is 155hp. It should be bumpin 165 now. The great thing is that Riva gets these engines to make some serious hp, and does it with bolt ons. That gives me piece of mind that if its not strong enough i can always do somethin about it. Im not out to dust everybody on the water, ALTHOUGH i got a few buddies with bass trackers with the 175 sportjets that id like to outrun....just for the hell of it :twisted:


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## PSG-1 (Nov 25, 2012)

I did shorten my impeller shaft, significantly. I did that because, the first time I did the boat, I started building without an engine or pump, I built the engine compartment based on a guess-timate, then realized it was a bit short once I got the engine and pump. So, rather than trying to re-build the engine compartment, I did cut the shaft, as well as the shaft housing of the intake tunnel.

Then, when I did the 4 stroke, again, having to keep it within the existing engine compartment, I had to cut the shaft and the housing even shorter. In fact, it's so short, that if I want to pull the impeller, I have to unbolt the engine, and I also have a set of flats cut on the shaft, inside the tunnel, so, I have to use a big wrench from the underside of the boat, and then use a pipe wrench to remove the coupler from the shaft, in order t be able to slide the impeller out.....what a PITA!

So, on my next build, I'll know better, to have an engine and pump sitting in front of me to base my dimensions on, instead of a theoretical figure that turns out to be too small for the actual thing.

You'll probably be able to run along with the Bass Tracker jets, but even if they are a few MPH's faster, the one advantage to the jet ski engine configuration, is that it's a better looking boat, it doesn't have that stupid hump in the middle. With a conventional 2 stroke engine, you can build the rear deck where it's all one level, as that's how mine was before I installed the 4 stroke. The 4 stroke, being a little taller, needs a higher cowling, but if you do it right, and make sweeping lines, instead of a big hump, it looks good, kinda like the cowling on my jetboat.


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## Imgoodatwhatido (Nov 26, 2012)

Got TERRIBLE TERRIBLE NEWS, yesterday i was riding the jetski, running 60 mph on the duck river lol what a rush. It sat down on me. I had to call a buddy to come get me. Checked the compression and it has ZERO pounds on the middle cylinder. :| So apparently now im gonna have a new engine in my boat cuz im gonna rebuild this damn thing!


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## PSG-1 (Nov 26, 2012)

Uh, oh! I HATE hearing stories like this!! I hate 'em because I've BTDT, and it really sucks! I went through it about 5 or 6 times with Tigershark engines in my jetboat, then, after it died the last time, I went with a Yamaha 4 stroke, and have had zero problems.

Anyhow, your problem sounds like it had an issue with detonation, especially if it has zero PSI in the cylinder. Because that's exactly what would happen when mine did it.

When you were riding, you had it at WOT, correct? Was there any kind of sound, like, a loud click? And then not going above around 3-4K RPM afterward? 

Take the spark plug out and look down the hole with a flashlight, bring the piston to TDC and see if there's a hole burned through it. If so, there's your trouble! 

At a very minimum, you will need a new piston and rings. 

That is, if the inside of the cylinder wall didn't get scored too badly when it detonated. If so, you'll also need a new cylinder sleeve. Some of the burned material from the piston could have also entered the bottom end, so, it's really advisable to go ahead and check that, if you possibly can. 

Pistons are made from aluminum, and any burned debris from the detonation MIGHT be OK in the bottom end, you may be able to just get by with a new piston, but I can't say for certain.


One thing is for sure, though. Before you run again, you need to drain the fuel tank, refill with new, clean fuel. You also need to service the carbs, especially that center carb, as it's obviously running lean. Make sure the jets are the correct size, and are not clogged. Give them a thorough inspection, and adjust according to manufacturer specs (consult a service manual) Then, when you run it, you need to do a 'throttle chop' at WOT, remove the plugs, and look at them carefully, so you know exactly what's going on, and can adjust accordingly.


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## Imgoodatwhatido (Nov 27, 2012)

yah i should have went over the engine before rippin it down the river. I chopped the ski and the engine is sitting in the shop floor now. I suppose since its out im gonna go ahead an build the entire engine. I dont know that i wont have the ports cleaned up by my old race bike guy. Im DEFINITELY removing the oiling system and usin premix. I might even go up a jet size on the carbs and squeeze all i can out of it. I am also gonna remove the intake and go with pod filters for each carb, and im gonna look at some after market exhaust options. This stock exhaust is huge and most of all its HEAVY as hell.


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## PSG-1 (Nov 28, 2012)

Imgoodatwhatido said:


> yah i should have went over the engine before rippin it down the river.



Yep, that's the one thing you have to be careful about with a ski that has sat for any length of time. Carb diaphragms can be damaged/dry rotted, jets can be clogged, and if you're running ethanol fuel, it can undergo phase separation. Any of these issues can cause a lean condition or detonation. When you're running, if you hear ANY sound like marbles rattling around in the engine, you'd better back it off, that's detonation and if you continue to run like that, you will blow holes in pistons, I know, because I've done it. 





> I chopped the ski and the engine is sitting in the shop floor now. I suppose since its out im gonna go ahead an build the entire engine. I dont know that i wont have the ports cleaned up by my old race bike guy.



If you don't already have one, get a service manual for that engine, this will help the re-build go a lot easier.




> Im DEFINITELY removing the oiling system and usin premix. I might even go up a jet size on the carbs and squeeze all i can out of it.




Smart move by going pre-mix. I don't trust an oil injection system. Get a block-off plate for the oil pump, and go with pre-mix. The only thing is that at idle, it will foul plugs more easily, but unless you're doing a lot of idling, like flounder trolling, you don't have to worry about that. The center carb jetting should be a little more rich than the other 2, as the center runs hottest, at least, that's how it was on the tigershark, I think the front carb was 105, the center was 135, and the pto carb was 120. 

Be careful about jetting too rich, this can be just as bad as jetting too lean. If it's jetted too rich, you'll get excessive carbon deposits, and this can interfere with proper heat dispersion across the top of the piston, this can also lead to detonation issues. I would go with the factory jetting, if the high speed is adjustable, then give it an extra 1/8-1/4 turn on the adjustment. If it's a fixed setting, then, I would go up one jet size from factory. Again, be sure to do a throttle chop at WOT, pull the plugs, and carefully inspect them. This is the only way to get a TRUE reading of what's going on.





> I am also gonna remove the intake and go with pod filters for each carb, and im gonna look at some after market exhaust options. This stock exhaust is huge and most of all its HEAVY as hell.



Don't use Pro-K flame arrestors with the clear plastic top. I've heard of instances where the suction actually caused this plastic piece to snap, and collapse, gagging the motor. It won't damage it, but if you're in a critical spot like a surf zone, inlet, or traversing some sharp turns, the last thing you want is for the motor to suddenly cut back, this leads to a loss of control. I ran the Pro-K arrestors on my tigershark, never had one collapse, but I heard of quite a few instances where they did.

Finally, if you're going with open stacks like that, you may need to adjust pop-off pressure in each carb (the manual will tell you exactly how to do this) With mine, I think we dialed it up to 21 PSI for the pop-off pressure.

As for the exhaust, yes, it is indeed quite heavy on all jet skis. It's a hollow-wall construction of cast aluminum, the hollow passages allow water to flow through to keep the head pipe cooled. Be careful with any modifications to the exhaust system, as the head pipe is constructed in a very specific manner for the proper amount of back-pressure, altering it in any way may not give you the results you're hoping for.

You may be able to find something like a Kaufman exhaust pipe, but be forewarned, they are expensive, and MUCH louder than the stock exhaust. 

Yeah, that chopping and rumbling sounds cool at first, but try riding a couple of hours like that, you'll get tired of a loud exhaust system real quick! At one time, I had my Tigershark straight-piped. When I fired up at the ramp behind the restaurant, it would damn near rattle the giant pane glass windows, and you could just about hear it from one end of the inlet to the other!

If you want to tone it down a little, two things you can do are to build a rear swim/boarding platform like my boat, and make the jet tunnel large enough that even with the pump bolted in, there's enough room at the rear of it (right above the wear ring/stator assembly) to mount an exhaust flange, and run the exhaust into the tunnel. Put some rubber skirting around the back of it, like they do with the newer 4 stroke yamahas, you'll be amazed at what this will do to cut down on the noise. 

For some ideas of the exhaust routing into the tunnel, you can check out some of my videos, it's clearly shown on one of our episodes of "American Jetboat" I think it's either episode 3 or 4.


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## Imgoodatwhatido (Nov 30, 2012)

im pretty sure K&N makes pods for this ski. If so thats what i will use. This boat will only be in freshwater and mostly on the river, and spark arrestors wont be used. As far as fuel goes i wont put ethanol gas in any 2 stroke engine.m I dont do any kind of trolling and will most likely be mixing the fuel pretty rich. Ill most likely use a 42:1 ratio. that should give me a ton of lube an give the engine a little more life. I havent made up my mind on jetting the carbs. I do know they are all getting tore down and rebuilt tho. I havent ruled out the idea of a ram jet type setup to push fresh air to the carbs. If I cant find an exhaust i like thats lighter and not so bulky i will probally re-route the stock exhaust. I can make a flange that comes off the header an puts the exhaust where i want it. The ski already has a riva sensor block off and a d-plate on it so i can do whatever i want with the exhaust without puttin the computer in a panic. The exhaust will definitely be thru-hull and underwater at idle so sound wont be much of an issue.


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## PSG-1 (Nov 30, 2012)

Sounds like you have a good understanding of these engines, so, I know you'll get it all worked out.

Once you're installing the engine, etc, if you run into any problems, consult my Aluma-Jet thread for detailed info an the various issues you may run into. If I haven't covered it, let me know, I'm sure I can come up with the answer.


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## Imgoodatwhatido (Nov 30, 2012)

I appreciate the help and the input. I think i will do the same as you did and shorten the impeller shaft as much as I can to keep my rear deck from being 5 feet long. When its all said and done im lookin for this to be a dual console bass boat type layout. Ive already got some plans drawn up. So far ive got the rod locker, front deck, and front storage compartments laid out on paper. Im a smallmouth junkie, cant get enuf of em!


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## PSG-1 (Nov 30, 2012)

I hear that! :mrgreen: 

Regardless of how you cut the pump shaft, you'll definitely want to use the spartan jaw coupler system. 

Your best bet is to cut the shaft down to the desired length, then, cut a shoulder, and then thread the end of the shaft, and then cut matching threads in that half of the coupler.

Depending on the configuration of the shaft side of the coupler, you may even have to bore out the coupler, TIG weld a piece of solid aluminum round stock in there, then put it on a lathe, and cut threads to match those of the shaft. Doing this operation on a lathe guarantees that the hole is perfectly centered, so it will run true, as the maximum amount of deflection is just .020"


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## semojetman (Dec 4, 2012)

This sounds like awesome build.

Cant wait to see some more pictures.

It is the big thing around my parts to put 4 stroke pwc engines in flat bottom boats, creating fast, light, shallow running sleds.

My buddy that is helping me with my boat has an 1856 BLAZER SS flat bottom with a 1200 Yamaha Waverunner engine and a pump out of a Yamaha jet boat.

It runs around 50 mph,
But i know another guy that has a like boat but with a 1500 Bombardier Supercharged engine that runs low 60s. Thats fast on the river.


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## PSG-1 (Dec 4, 2012)

Yeah, that's the engine I want to use on my next build, the 1494 cc 4-tec, intercooled, supercharged engine with 215 HP. Those things are wicked! :mrgreen: :mrgreen: :mrgreen: 

Just have to make sure to use an '07 model or higher, as the earlier models had some issues with the supercharger bearings, or something like that.


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## scubapro820 (Dec 5, 2012)

I would really like to see this thing go !!! I did a similar build like psg-1 did before he went to a yamaha engine. got a tigershark1000 suzuki tuned to about 130hp. used a gp 800 pump 10mm smaller than a 1200. im at 18/21 pitch and need to go bigger to get my speed up im at 3/4 throttle and 6k rpm @ 42mph i should get 45mph and if you look at my boat its a giant parachute! but for me on the big muddy it keeps the river out of my boat and the sun out of my eyes ! anyhow I've noticed the short boats like ours like to porpus and trim wind and current and loading effect the trim severely psg went for a reverse gate i went with trim and when im in those mixes with wind passengers and changing current and wind i can fix it on the fly. 

but the #1 thing to do is research and innovate!!!!!!!!! you should build it your way, we are all engineering our boats to be the best for what we want and it is the only way to make an excellant unique innovative piece of engeneering! The sky is not the limit here!!


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## semojetman (Dec 6, 2012)

Yeah, my mom had 2 2003 sea doos and she had alot of troubles. Tore up a supercharger in one.


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## PSG-1 (Dec 6, 2012)

semojetman said:


> Yeah, my mom had 2 2003 sea doos and she had alot of troubles. Tore up a supercharger in one.



IIRC, it was something to do with a sleeve on the supercharger turbine shaft. I think the older ones were ceramic, which would stress crack and shatter at high speed, especially if they hit some moisture, and they changed them to titanium.


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## Imgoodatwhatido (Dec 9, 2012)

its definitely in the works, although I been laid up in the house for 4 days with the flu and havent touched it. I think this engine will push this sea ark very good. Im just waiting for a little extra funds to buy my jet pump and engine rebuild kit. Other than that the engine is pulled out and everything is setting in the shop floor ready to be installed, but nothin will get put in until the jet pump is installed.
The pump will determine where everything will go. Im gonna try to keep from trimming the driveshaft down, but if i have to in order to get my rear deck the length i want...then i will


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## PSG-1 (Dec 9, 2012)

Imgoodatwhatido said:


> its definitely in the works, although I been laid up in the house for 4 days with the flu and havent touched it. I think this engine will push this sea ark very good. Im just waiting for a little extra funds to buy my jet pump and engine rebuild kit. Other than that the engine is pulled out and everything is setting in the shop floor ready to be installed, but nothin will get put in until the jet pump is installed.
> The pump will determine where everything will go. Im gonna try to keep from trimming the driveshaft down, but if i have to in order to get my rear deck the length i want...then i will






Well, it appears that you already understand a concept that I failed to understand on my first build....that the pump is the first thing to install, as it determines where everything else goes. 8) 

That's why the shaft on my pump has been chopped so short. On the next build, I will know better. When I did mine, not many people were doing this, and there weren't many (if any at all) internet forums with knowledgeable people willing to help. So, I was on my own with that project, doing everything by guess-timation, and trial and error.


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## Imgoodatwhatido (Jan 26, 2013)

well it came in today, its time to start chopping and fittin it together. Christmas put a damper on my wallet so I havent got much done as of lately.


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## Imgoodatwhatido (Jan 26, 2013)

As far as that half inch. I plan on shortening the shaft tube, and the shaft as well. This should shorten the pump by at least 6 inches. That will allow me to machine the front of the pump to match the rear.


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## scubapro820 (Jan 26, 2013)

I want to see more pics on this thing I'm excited to see your design


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## PSG-1 (Jan 27, 2013)

Imgoodatwhatido said:


> well it came in today, its time to start chopping and fittin it together.



All right! =D> 

That's a pump from a GP1200. I can tell, because the threaded dogs are on the sides of the exit nozzle, instead of on the top and bottom, like the XL1200. That's because the GP1200 uses a trim ring between the thrust nozzle and the steering nozzle, where the XL uses a reverse bucket that's mounted to the steering nozzle. 

Trim is great for fine tuning the boat's attitude for varying loads. However, because the GP has a trim system, it does NOT have a reverse like the XL1200. So, if you want a reverse system, you will have to buy a reverse gate for something like a Yamaha VX110, and make a set of mount brackets that attach to your transom. Then mount the reverse gate to that, and use a push-pull cable to operate the reverse system, along with another push-pull cable for your trim system. Trust me, reverse is a nice thing to have for smoothly docking and trailering your boat.

When you get ready to mount the pump, find the centerline of your boat, then carefully measure your cut-out, keeping it squared and centered with your reference line. After mounting the pump, put the engine in position, and then determine how to build your mount system that will bring the engine coupler into alignment with the pump coupler. Ranchero and me built rail-type mounts, although, Ranchero's design is a little better than mine, because it allows for some adjustment.

If you are using a spartan jaw coupler, when you are aligning the engine, use a straight edge, laid across the 2 halves of the coupler, then use a feeler guage to check for mis-alignment. The maximum allowable mis-alignment is about .020", any more than this can cause premature bearing failure of the pump. This is the most critical operation of the entire build, so, take your time, and be as precise as you can. I got mine within about .010", which is pretty precise, all things considered.


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## PSG-1 (Jan 27, 2013)

Imgoodatwhatido said:


> As far as that half inch. I plan on shortening the shaft tube, and the shaft as well. This should shorten the pump by at least 6 inches. That will allow me to machine the front of the pump to match the rear.









You can cut the tube all the way back to the fat section just behind that first tube support strut. The bearings and seals are farther back than this, pretty much at the very back end of the tube.

One thing you can do to beef it up a little bit, is to get a set of self-lubricating bronze sleeve bearings. Get an inner, and an outer bearing. For the inner, you want to bore it where it's about .001-.002" larger than the driveshaft for its ID, then, turn the OD to a size that will match the ID of the outer bearing (you'll have to machine that ID as well) Best to machine this where it's a press fit, or even an interference fit, where one part is heated and the other part is chilled, then put together.

Finally, machine the OD of the outer bearing sleeve where it's the same as the ID of the shaft tube. To secure this bearing into the tube, you can drill and tap the tube and bearing sleeve, then install a zerk fitting. This will act as a retainer, as well as giving you the ability to lubricate the forward end of the shaft with a few pumps of grease about every 10 hours. The bronze sleeve bearing helps absorb vibration and deflection, and cuts down on excessive wear to the rear bearing and seals. It's like a carrier bearing.


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## Imgoodatwhatido (Jan 27, 2013)

Remember that I still have all the parts from the 2004 ski. So I have all the trim and the reverse bucket at my disposal. I should be able to remove this cone and put the cone from my xlt pump on it. Then everything should bolt right up. I'll look into the pump mod and see what I can come up with. Its hard for me to visualize what your talking about without it setting in front of me. This pump I just bought has what looks to be a nearly new impeller in it. Either that or its in really good condition. Not a nick on it. The wear ring is really tight as well. I know of a company called Timken. They make extremely high quality bearings for most any application. We use to use them a lot on a gigantic stretch film press I use to run. They make ceramic sealed bearings that last an extremely long time. Those machines ran several thousand RPMS nonstop 24 hours a day, 7 days a week, and those bearings were changed once a year whether they needed it or not. I may go with something like that. Once I get the pump milled to where i want it Im going to weld it to a boot to get the desired fit I want. When its all said and done when I bolt the pump in I will be bolting 2 pieces of 3/8" aluminum together. I still need a center jug for the engine and a rebuild kit. Its gettin deep $$$$$$$$$$$$ lol


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## PSG-1 (Jan 27, 2013)

Imgoodatwhatido said:


> Remember that I still have all the parts from the 2004 ski. So I have all the trim and the reverse bucket at my disposal. I should be able to remove this cone and put the cone from my xlt pump on it. Then everything should bolt right up



An XLT thrust nozzle should bolt up to the GP stator assembly, the bolt pattern is the same, they are both 155mm pumps.






> . I'll look into the pump mod and see what I can come up with. Its hard for me to visualize what your talking about without it setting in front of me.





Well, if you run into any issues or have any questions, let me know, I'll be glad to help out with some advice based on my own experience with a similar pump.







See, the 2 pumps are virtually identical. You can see how I cut down the shaft housing on mine.





> This pump I just bought has what looks to be a nearly new impeller in it. Either that or its in really good condition. Not a nick on it. The wear ring is really tight as well.






Max allowable clearance from impeller to wear ring is about .025" Any more than that, means the prop, or the wear ring are worn and need to be replaced for maximum pump efficiency. I think minimum clearance is about .005" Props can be rebuilt by a company called "Impros" They can also re-pitch any prop to your specs.






> I know of a company called Timken. They make extremely high quality bearings for most any application. We use to use them a lot on a gigantic stretch film press I use to run. They make ceramic sealed bearings that last an extremely long time. Those machines ran several thousand RPMS nonstop 24 hours a day, 7 days a week, and those bearings were changed once a year whether they needed it or not. I may go with something like that.



I've heard of Timken bearings. But here's the issue....getting bearings that have an ID the EXACT size for the OD of the shaft, AND having the OD being the exact size of the ID of the pump shaft housing. This is why I say go with the oil-impregnated, self-lubricating bronze sleeve bearings, you can machine them to whatever size you want. And they work. 

In fact, take a look at an online parts diagram of your pump. You will see that in addition to the 2 seals and the bearing, there is a forward bearing that has a splined rubber outer housing. The forward bearing itself is nothing more than a bronze sleeve bearing.





> Once I get the pump milled to where i want it Im going to weld it to a boot to get the desired fit I want. When its all said and done when I bolt the pump in I will be bolting 2 pieces of 3/8" aluminum together.



I'm not following you on this. :?: When you say 'boot' do you mean coupler? If so, what you want to use is a spartan jaw coupler, it's two inter-meshing disks with cogs, cast from aluminum, and there is a rubber 'spider' that goes between them, to eliminate the metal-to-metal wear, and some deflection and mis-alignment. 

Note that I said "some" mis-alignment. You'll still have to be within .020" with your alignment, regardless of which type of connection you use. Any more than this will cause premature wear of the pump bearings.

Or when you say "boot" are you referring to making a wedge-shaped piece to deal with the angle of the pump where it goes into the boat? That was a real PITA when I did my build, I cut tapered strips of aluminum, and made a tapered 'shelf' for the pump to fit tightly against.



> I still need a center jug for the engine and a rebuild kit. Its gettin deep $$$$$$$$$$$$ lol



If you haven't done so already, check SBT, they rebuild jet ski engines, and they sell all types of parts and rebuild kits.


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## Imgoodatwhatido (Jan 27, 2013)

im gonna remove the 1/2 inch of lip on the bottom of the intake housing. Once removed im gonna weld some 3/8 plate aluminum to make a surface to bolt to. Im more or less gonna redesign the intake housing.


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## PSG-1 (Jan 27, 2013)

OK, I got ya now. You're basically making a mounting flange for the duct. 

The only issue is that if you ever have to replace the duct, you're going to have to go through the entire process of modifying it all over again. I would imagine it would take almost as much time to modify the duct, as it would to configure the boat so the factory duct will bolt right up.

For example, on the first version of my jetboat, I had a lot of customized and modified parts. When I did the second configuration, I tried to move away from having to modify factory parts when possible, I re-configured things so the factory parts would work without modification, instead of modifying parts to fit the existing configuration.



It's something to consider.


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## Imgoodatwhatido (Jan 27, 2013)

damn, that makes sense. Advice appreciated


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## PSG-1 (Jan 28, 2013)

Here ya go:


This one shows the hull, and the inner floor plate made from 1/4" aluminum. The engine mounts are welded to this plate.






OK, in this one, you can see the "wedge" I'm talking about. That was a major PITA. This operation is best done with the boat upside down....trust me on this! I did it the hard way, with ME being upside down. Won't do it that way again, I can guaran-damn-tee you that.






This one shows the box form that gets welded into the transom. It's also made from 1/4" plate






You'll also need to form a sealing ring by rolling a strip of aluminum, and welding it, like this:







From the rear, you can see the radius of the box, where the pump will fit








And this one shows the pump, bolted up:


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## Imgoodatwhatido (Jan 28, 2013)

once the pump was installed, how did you get the sealing ring to seal against the pump?
It looks like some type of silicone maybe?


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## PSG-1 (Jan 29, 2013)

Imgoodatwhatido said:


> once the pump was installed, how did you get the sealing ring to seal against the pump?
> It looks like some type of silicone maybe?




Actually, it was 5200, which became a lesson well learned....to NOT ever use 5200 for anything removable!! Turns out I had a mis-alignment which damaged the bearings, when I had to pull the pump, I found out that 5200 doesn't come loose :shock: That pump had to come out in tiny little pieces, after busting it apart with a BFH. Which, in this case, was OK, because the shaft housing was also damaged when the bearings failed (again, alignment is a very important factor)

So, lesson learned, don't use 5200, use RTV 'Ultra Black' silicone.

The way you want to do it is to put a bead of sealant on all mating surfaces, then, bolt the pump into the boat, as you tighten the bolts, the silicone will mash out of the gaps, indicating a proper seal. 

It's definitely a 2-man operation, you'll need an assistant to help hold the pump tunnel, while you install the two bolts on the forward end. 

Also, you want to have the wear ring, stator, and thrust nozzle in place on the pump when you do this (use the 4 long bolts that hold the pump assembly together) This way, you can go ahead and tighten the 2 bolts that hold the wear ring, and the 2 bolts that hold the thrust nozzle, as this will support the rear end of the pump.

You can tighten the two bolts on the forward lip, and you can also go ahead and thoroughly tighten the 2 bolts that holt the wear ring in place. But, do not overtighten the thrust nozzle bolts, you only want to tighten them enough that they don't rattle. Excessive tightening of these 2 bolts will put the pump in a bind.

Once you have the pump bolted in, allow the RTV silicone to cure, then, tilt the boat up, put the plug in, and fill the stern with water, and look for any leaks. If there are no leaks, then proceed to install the driveshaft and impeller assembly.


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