JetJon Conversion - SeaDoo SP into 1236 Fisher

[JMichael]

Sorry, I didn't get any pics. There was a bolt that held the handle to the spool, it was only a #10 size and couldn't handle the load. So I drilled out the cone washers on each end and put a much larger bolt with a 5/16 body and 1/4-20 thread end, and assembled everything with lots of grease. Then I lengthened the handle by 2".

My anchor weighs in at 12 lbs, I can crank that up easily now. Hitting a snag doesn't cause a problem now either, I can let some rope back out and work the rope by hand till I free the anchor, then I finish cranking it up. There are no bearings in the design so I don't know how long it will last, only time will tell, but I think it's going to work out ok.

I'd like to know if there is any difference in design between the Attwood brand, and the Worth. They look similar in appearance, the Worth is more expensive though, maybe the internals are better designed?

I'm not sure what brand mine is because it came with the boat but it looks exactly like yours. I haven't figured out how to get the spool/hub off to get at the inner workings of it yet. I was planning on using a 15-20 lb anchor on mine so it would hold when I take it to the rivers here.

 

[painlesstom]

I'm not sure what brand mine is because it came with the boat but it looks exactly like yours. I haven't figured out how to get the spool/hub off to get at the inner workings of it yet. I was planning on using a 15-20 lb anchor on mine so it would hold when I take it to the rivers here.

Here are a few pics that might help make sense of some things. The bolt is what I replaced, the factory used a small #10 with Phillips head. The nut is on the opposite side of the spool under the mounting pad. I wouldn't recommend anything over 15 lbs. Trac makes a 12v anchor hoist that is rated to 25 lbs that might work well for you. Hope that helps.

 

[painlesstom]

Which strainer are you using now? Factory, or something else? If you're not using a factory-type strainer, get a Yamaha bilge strainer and mount it in the very back corner of the bilge, where the floor meets the transom.

The other problem with drainage in jetboats is that because of the jet pump tunnel, when water runs to the stern, the tunnel acts like a divider, some of the water goes to the starboard side of the tunnel, and some runs to the port side. So, unless you have a bilge on BOTH sides, you can never keep all the water pumped out. (I suspect that's why you're getting some water in your boat) This is why I have my 1100 and my 800 GPH pumps on the starboard side of the tunnel in my boat, and then the suction strainer on the port side, for any water that the other pumps don't take out.

I've got the factory Seadoo dual pickups that were mounted right behind the PTO on either side of the tunnel. I moved them further back which will help alot. With the Seadoo hull splitting the hull down the middle, water would take three paths. Port, center, and starboard. The Jon boat drain plug is on the starboard side, so I put my 800 gph 12v on port side leaving the siphon pickups center. So I had water from both sides that never got near the siphon pickups. I simply sealed off both sides so any water taken on in front of the deck would be forced to drain to the center and to the siphons. If I end up taking on enough water to put the 800 to work, then that is when it would be worth it's weight in gold. I hope I never have to use it. I'll get some pics of how it's set up soon, too many things going on and forgot.

Indeed! If it's anything like my experience with my boat, people almost break their necks staring as it whizzes by, with a puzzled look on their face like "where's the motor on that thing?" It's always fun to race them, too. Anytime I go inland, I always see somebody in one of those little fast crafts or bug buster type boats with a souped-up outboard, and I always enjoy running alongside them.

Not just inland, but here, as well. We've got a guy out here with one of those go-devil surface drives on his boat, he thinks he owns the creek at low tide because of where it can go. Correction, he THOUGHT he owned the creek, until I blasted by him one day, passed him like he was sitting still, then went 100 yards up the creek from him, did a 180 spin at 30 MPH, and blasted back by him. The look on his face, and his passenger's faces was great, wish I'd had my camera for that one! :mrgreen: :mrgreen: 8)

These boats are certainly unique, I'm really surprised a company hasn't produced something similar. There definitely seems to be a market for something like it. But then again, maybe not, most of the people who I've talked to that wanted one, couldn't afford one anyhow. Doesn't hurt my feelings though, I like being the only one around with a Jet Jon. lol :lol:

 

[PSG-1]

These boats are certainly unique, I'm really surprised a company hasn't produced something similar. There definitely seems to be a market for something like it. But then again, maybe not, most of the people who I've talked to that wanted one, couldn't afford one anyhow. Doesn't hurt my feelings though, I like being the only one around with a Jet Jon. lol :lol:

The only factory-production jet john I've ever seen is the Tracker with the 175 Mercury Sport Jet. And I don't like the way they have the motor in a vertical configuration with a 2 foot high doghouse in the middle of the rear deck. The horizontal engine configuration like our boats looks much sleeker.

On one hand, it would be cool to get into building these boats. But on the other hand, I like being one of the rare few that has a boat that can travel through areas that you'd ground a kayak trying to cross (like the serpentine channel in my video 'low tide- high output')

 

[painlesstom]

Yup, and the 175 drinks gas quickly. I've got a 14' Sea Rayder w/ Sport Jet 90 that you can watch the fuel gauge drop with every mile. I've also seen some with the Optimax 200, which is supposedly better on fuel, but I'm sure no where as near as efficient as our lighter boats. I've put 50 miles on GPS since I filled my tank, have used roughly half, which gives me around 11 mpg so far. I am very happy with that.

It wouldn't be half as fun if everyone had one. Anyone who sees my boat now, asks if I built it. Look what happened with choppers in the Harley scene... oops. Now nobody cares and building one doesn't matter, selling one is almost impossible anymore.

 

[PSG-1]

Yup, and the 175 drinks gas quickly. I've got a 14' Sea Rayder w/ Sport Jet 90 that you can watch the fuel gauge drop with every mile. I've also seen some with the Optimax 200, which is supposedly better on fuel, but I'm sure no where as near as efficient as our lighter boats. I've put 50 miles on GPS since I filled my tank, have used roughly half, which gives me around 11 mpg so far. I am very happy with that.

Damn skippy! I'd be happy with that, too! That's outstanding gas mileage for a boat. My FXHO gets about 5 MPG on average cruising speed, and it's a 4 stroke! But then again, I am pushing 1225 pounds (boat fully loaded with fuel) then my weight, plus any passengers on top of that. The good thing is that regardless of number of passengers, or regardless of what purpose I'm using the boat for, including waterskiing, the gas mileage doesn't change much.

It wouldn't be half as fun if everyone had one. Anyone who sees my boat now, asks if I built it. Look what happened with choppers in the Harley scene... oops. Now nobody cares and building one doesn't matter, selling one is almost impossible anymore.

Absolutely right! But it would be cool to be one of the first people to try and corner the market of jet jons if there ever was such a market. Heck, like I said, maybe even get a TV show and call it American Jetboat. I'm not really a fan of choppers, but I am a fan of boats, guarantee I'd watch the show.

But then again, like I said before, I like being one of the lucky few with the unfair advantage of being able to go where other boats can't. :twisted:

 

[Ranchero50]

Good looking little boat. I second the grab rails around the windshield, they make floating while floating a safer proposition.

On mine I also went with the pin type swivel seat posts so I can move my seats around. The swivel isn't an issue at speed and makes 'working' from the drivers seat more comfortable.

You should be able to get a stock Seadoo tach and wire it in.

Good job and enjoy it.

 

[painlesstom]

Damn skippy! I'd be happy with that, too! That's outstanding gas mileage for a boat. My FXHO gets about 5 MPG on average cruising speed, and it's a 4 stroke! But then again, I am pushing 1225 pounds (boat fully loaded with fuel) then my weight, plus any passengers on top of that. The good thing is that regardless of number of passengers, or regardless of what purpose I'm using the boat for, including waterskiing, the gas mileage doesn't change much.

That was part of my goal for this build, to keep fuel mileage a priority. My Mokai gets 25 mpg, but with a top speed of 15mph it isn't going to win any races. For the Jon boat to get 10+ mpg, well, that makes me very happy.

Absolutely right! But it would be cool to be one of the first people to try and corner the market of jet jons if there ever was such a market. Heck, like I said, maybe even get a TV show and call it American Jetboat. I'm not really a fan of choppers, but I am a fan of boats, guarantee I'd watch the show.

But then again, like I said before, I like being one of the lucky few with the unfair advantage of being able to go where other boats can't. :twisted:

That would require an immense amount of startup capital, which would present the biggest challenge. Get that show going and I'll watch every episode, being a part of it could be fun, but the spotlight isn't the seat for me.. lol

Unfair advantages are only unfair to those without... I will happily wave to anyone as I skim by over top of the shallows. :lol:

 

[painlesstom]

Good looking little boat. I second the grab rails around the windshield, they make floating while floating a safer proposition.

On mine I also went with the pin type swivel seat posts so I can move my seats around. The swivel isn't an issue at speed and makes 'working' from the drivers seat more comfortable.

You should be able to get a stock Seadoo tach and wire it in.

Good job and enjoy it.

Thanks man, I watched your videos many times before, and during, my build. Good job yourself! 8)

 

[painlesstom]

Weather warmed up and I made it out for a nice ride. 21 miles round trip and got some video using the anchor, which has been working much better.

This is the 10.5 mile return trip. -> https://www.youtube.com/watch?v=T7cB-xGvwuo

 

[64coupe]

Hi Great build and a lot of information to help me with mine!

Do you keep the boat indoors heated or climate controlled? What are your winters like?

I am considering fiberglass but wanted to know how you prepped your surface. It looks as though you put on the glass/resin with out cleaning off the paint. Resin would probably eat through the paint though haha. How is it holding up this season, any leaks or concerns?

I am considering this same idea but I have heard the aluminum oxidizes almost immediately after the paint is cleaned off and aluminum and fiberglass have yet to be something of a permanent use.

 

[painlesstom]

Thanks, it is stored in my garage but not climate controlled. The joint between the fiberglass hull and the aluminum hull is sealed with polyurethane and bolted together with 30 + 1/4-20 stainless bolts. The fiberglass I added was to add rigidity to that union, I sanded down and cleaned all the fiberglass hull so the fiberglass I added would stand a better chance of adhering to it, but wasn't worried about it sticking to the aluminum. It is just making the jet ski hull footprint larger so the weight was evenly distributed over the entire floor of the boat. There is no flex, no leaks, and I do not expect any. This method works well, but I would not recommend it for areas where you might encounter rocks.

Let me know how your build progresses, I would like to follow your thread if you start one. Good luck!

 

[64coupe]

Thanks, it is stored in my garage but not climate controlled. The joint between the fiberglass hull and the aluminum hull is sealed with polyurethane and bolted together with 30 + 1/4-20 stainless bolts. The fiberglass I added was to add rigidity to that union, I sanded down and cleaned all the fiberglass hull so the fiberglass I added would stand a better chance of adhering to it, but wasn't worried about it sticking to the aluminum. It is just making the jet ski hull footprint larger so the weight was evenly distributed over the entire floor of the boat. There is no flex, no leaks, and I do not expect any. This method works well, but I would not recommend it for areas where you might encounter rocks.

Let me know how your build progresses, I would like to follow your thread if you start one. Good luck!

Thanks for your input! I really do enjoy forums the wealth of knowledge is awesome. Who makes the polyurethane that you used? I like the idea of spreading the footprint of the ski's hull I did not think if it like that. Is your engine still the single carburetor?

I did start a thread. https://www.tinboats.net/forum/viewtopic.php?f=21&t=30328 I have been thinking about the use of rubber as a gasket between the aluminum and the fiberglass of the ski. And yes I may encounter a rock so I will try to only expose the ride plate and pump inlet on the bottom of the hull.

 

[painlesstom]

I replied to your thread and subscribed.

Yes, my engine has a single carb. Plenty of power for what I need, a flat bottom 12' Jon boat has no business going faster than 36 mph anyhow. :LOL2: I wanted the smallest Seadoo motor to keep fuel consumption down, 11 mpg is the result, but it's still a thrill to blast around in.

Getting ready to build a grab bar around the windshield, will make moving around easier from front to rear.

 

[painlesstom]

Finally got the grab bar made and installed, makes such a difference in moving around the boat now. Got some fishing in on the GoPro so I could share the trip with everyone.

https://www.youtube.com/watch?v=AdbgkBgLzDo

 

[PSG-1]

Good addition/upgrade!

I put a grab rail above my windshield a couple of years ago, after doing a full-body plant in the boat early one morning at the boat ramp, when the boat was slick with dew. LOL, fortunately, no one saw that.

 

[Ranchero50]

Good build. You should be able to pick up for the tach off one of the Mpem wires and use a Seadoo tach. I think I just had to add a resister to match what the electrical schematic called for.

One neat thing is once the 587 goes south you can put a 717 in it and really fly.

 

[PSG-1]

I ran a Teleflex tachometer off my Tigershark engine, and it worked correctly. I had to fiddle with the potentiometer adjustment on the back of the tach to get it dialed in to read correctly, but once I did that it worked fine.

As per ABYC codes, most of the time, tach wire is going to be green. But the sure way to find out is to use a little 12V test light. Hook the negative lead to a negative wire, then, put the positive lead on the wire you believe is the tach wire. Start the engine and see if the light pulses. If so, this is the tach wire. If the light stays on with no pulsing, this would be an ignition wire.

When testing like this, it's a good idea to use little 1 amp glass fuses rigged inline on the positive wire, in case you cause a short, you won't fry anything except a fuse.

 

[Ranchero50]

The Seadoo tachs don't pick off the ignition coil as they are running a hybrid magneto setup, they sense off the generator wiring. I had to check the schematic, yellow / black wire thats going to the rectifier gets split off and a 20K ohm resister installed inline turns into a grey wire that goes to the tach sense on the Seadoo tach. The other two wires for the tach are plug and play with the rest of the Seadoo gauges.

https://www.ebay.com/itm/SEADOO-97-96-GTX-787-800-OEM-TACHOMETER-RPM-GUAGE-278001051-TACH-GAUGE-/181178318152?pt=Personal_Watercraft_Parts&hash=item2a2f11bd48&vxp=mtr

The tach was one of those WTF moments on my build just trying to figure out what would work and read correctly. eVilbay saved the day.

 

[painlesstom]

I've already added a tach... just a simple tiny tach type version with hour meter. Works fine for what I need.



I'm not sure the 717 and 580 use the same MPEM, I chose the 580 for it's smaller size and lower hp for the sake of better fuel efficiency. If I ever need to replace it, I'll go with another 580.

My next project I will be using a 94' Seadoo XP with the 657 motor that I have, should keep me busy this winter.