Alumacraft MV1448 Seadoo IB jet, Still jetting

JasonD
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Re: Alumacraft MV1448 Seadoo IB jet, Still jetting

Post by JasonD » 30 Sep 2014, 13:08

Ranchero50 wrote:Hey guys, sorry I haven't been paying attention to this thread. NewRiverDan1, per the bottom protection, I just try to avoid the hard stuff on the bottom. I really want to put steel flex on the outer hull some winter and see how that does.

JasonD for the pump mounting plate, 90` to the bottom of the hull and high enough that you can maintain no drive line misalignment. On mine the bottom of the pump was @ 1/4" above the bottom of the hull. For fabbing the plate, I could do it but you'd need to supply the 3/4" aluminum plate. Per the trim, I think you can add the trim nozzle setup to a non trimmed pump 140mm pump without issue. You should do some research onto that.
Thanks for the info on your set up. Plan is right now to mount the pump where it needs to be and then use that to align my motor mounts. I'm figuring around some ideas to make up a plate to hold the pump but might work something out with you in the end. I've priced a few VTS I've seen on ebay and I plan to get the rig running first and look at retro fitting later. This thread is such a great resource, thanks

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Ranchero50
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Alumacraft MV1448 Seadoo IB jet, Still jetting

Post by Ranchero50 » 30 Sep 2014, 15:05

The curse of the pump mount flange was the pump had a step on the front edge that I needed a recess for, thus the 3/4" plate. That also gave me a solid point to weld the pump inlet to and over the last couple years has worked very well. Honestly, I'm surprised this boat has done as well as it has because for most the original pump work my shielding gas hose was clogged with mud dauber nests and those welds are rather porous. :)

When you mount your pump you want the axis of thrust with the trim set neutral to match the axis of travel with the boat running flat out. If it's down the nose will plow and really handle like a dog. If it's too high you'll either porpoise or run slow as your thrust isn't impinging on the standing water. With the trim I just bump it up until it slows and then drop it back a little bit. The motor tone changes and the boat scoots along a couple MPH faster. Of course it's not shooting a rooster tail then either.

Also when you do your pump inlet, try to minimize the tunnel size and length. At low speed you really need a lot of volume or it'll cavitate. At high speed you don't need as much volume as the opening will create drag. It took me two shots to get one that worked well and I think the sport jet grill helped make the design parameters that would work with the 140mm pump. Along with the size of the opening, you really want the opening as far back as is practical and try to allow passages between the strakes and the side of the opening for air to escape. With a mod V or straight flat bottom you will ingest air and if you can't get it to bypass the pump you will cavitate and have troubles. My spoon 'cured' my problem unless I'm in while caps. Oh yeah, when the opening is close to the transom it's a whole lot easier to clean too.

Good luck and post a link to your build thread. I tried to describe what and why I was doing stuff on this thread to help others and love to see how they did stuff as well.

Jamie

JasonD
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Re: Alumacraft MV1448 Seadoo IB jet, Still jetting

Post by JasonD » 30 Sep 2014, 19:24

I will post a link and share as well. You developed a great build but worth that little detail of having a CNC just sitting in your garage it puts it at a level out of reach to most people. I have an idea to incorporate the ride plate into the build to deal with the pesky step on the flange. While I would much rather have your pump plate this, hopefully, simplifies the build and you don't have to eat the cost of 3/4" aluminum plate :o Plan to keep this as a rig that can be built with minimal specialized equipment. As for my intake I am currently working on mimicking the tunnel shape of the ski it came off of. Thought being that is what seadoo decided the optimum water flow needed for the pump. Right? Who knows but it at least sounds good to me lol. This build intrigues me on the challenge of building such a vessel and trying to do it for minimal cost. Paid $100 for the seadoo, traded an old canoe for a 1448 monark boat and only out a few parts to get the ski running so far. I won't clog your thread up with my build but will make sure to update along the way, have a thread currently in another forum.

JasonD
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Re: Alumacraft MV1448 Seadoo IB jet, Still jetting

Post by JasonD » 30 Sep 2014, 21:51

By the way, the spoon is genius and I will be stealing that fir my build.

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Ranchero50
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Alumacraft MV1448 Seadoo IB jet, Still jetting

Post by Ranchero50 » 27 Jun 2015, 20:42

Welp, this is officially ridiculous... I still haven't splashed my boat yet this year. I'm ready to and want oo but mother nature is pouring on us. Heck, my garden even drowned.

Just venting.

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PSG-1
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Alumacraft MV1448 Seadoo IB jet, Still jetting

Post by PSG-1 » 27 Jun 2015, 21:15

Don't feel bad, Ranchero....it's been 2 months since I've been on the water with my jet boat. I know, right? :? One day, I gotta get to the river and test it out now with the Line-X on the bottom and with the new impeller and wear ring.
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BigTerp
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Alumacraft MV1448 Seadoo IB jet, Still jetting

Post by BigTerp » 29 Jun 2015, 12:52

Ranchero50 wrote:Welp, this is officially ridiculous... I still haven't splashed my boat yet this year. I'm ready to and want oo but mother nature is pouring on us. Heck, my garden even drowned.

Just venting.
That sucks!! Was just getting ready to PM you to see if you've been out and how you've done. We got out Friday evening before all the rain over the weekend. Did OK. The river is a mess right now!!! Hoping it gets down to manageable levels by Thursday so we can get out again.
BigTerp's Tracker Sportsman 16' build-------> http://www.tinboats.net/forum/viewtopic ... 21&t=26774

JoshKeller
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Alumacraft MV1448 Seadoo IB jet, Still jetting

Post by JoshKeller » 30 Jun 2015, 00:40

BigTerp wrote:
Ranchero50 wrote:Welp, this is officially ridiculous... I still haven't splashed my boat yet this year. I'm ready to and want oo but mother nature is pouring on us. Heck, my garden even drowned.

Just venting.
That sucks!! Was just getting ready to PM you to see if you've been out and how you've done. We got out Friday evening before all the rain over the weekend. Did OK. The river is a mess right now!!! Hoping it gets down to manageable levels by Thursday so we can get out again.

with this rain, we SHOULD have water until late july to run pretty much anywhere.

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BigTerp
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Alumacraft MV1448 Seadoo IB jet, Still jetting

Post by BigTerp » 30 Jun 2015, 09:55

JoshKeller wrote:with this rain, we SHOULD have water until late july to run pretty much anywhere.
That would be nice. I can't complain with the water levels. Last year it got pretty low and I managed to punch a hole and destroy my foot. Don't want to repeat that again this year!!
BigTerp's Tracker Sportsman 16' build-------> http://www.tinboats.net/forum/viewtopic ... 21&t=26774

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Ranchero50
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Alumacraft MV1448 Seadoo IB jet, Still jetting

Post by Ranchero50 » 25 Jul 2015, 22:55

We finally made it out tonight. Engine fired off with enough smoke to stir the neighbors out of their stupors but it cleared up. Put 2 gallons of high test in it and hit the water. Plugs weren't too happy with the extra oil so we took it easy going up river. Felt good to finally wet a line and we put three hours on the water and got a really up close and personal fireworks display that at first sounded like gunfire. The run back down was fine, smooth and back to normal.

Good times.

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Alumacraft MV1448 Seadoo IB jet, Still jetting

Post by snowfighter » 22 Aug 2015, 19:55

Thanks for sharing so much detail. I am on the hunt for a jetski

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Ranchero50
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Alumacraft MV1448 Seadoo IB jet, Still jetting

Post by Ranchero50 » 04 Jul 2017, 12:37

So,so disappointing. Looks like I'll have to do something about the build pictures since photobucket is no longer allowing 3rd party image hosting. In the meantime if you right click on the clocked image and copy the image location you can open a new tab, paste the link and see the picture. Again, disappointing.

CedarRiverScooter
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Alumacraft MV1448 Seadoo IB jet, Still jetting

Post by CedarRiverScooter » 04 Jul 2017, 12:47

Nice to hear from you Ranchero.

We hit a snag yesterday, literally.

It dented the spoon & worse yet tore a thumb sized hole in the jet ski glass. Fortunately the hole was up & behind the spoon's trailing edge, so as long as we kept going, we didn't take on water. This was a hunch on the fly - was good decision not to stop & check it out!

This craft is definitely a hobby!

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New River Rat
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Alumacraft MV1448 Seadoo IB jet, Still jetting

Post by New River Rat » 04 Jul 2017, 17:29

Ranchero50 wrote:So,so disappointing. Looks like I'll have to do something about the build pictures since photobucket is no longer allowing 3rd party image hosting. Again, disappointing.

I think we need to hit 'em with a class action suit.....
My Tinny is a tool, a means to an end, if you will.

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Ranchero50
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Alumacraft MV1448 Seadoo IB jet, Still jetting

Post by Ranchero50 » 05 Jul 2017, 19:40

Nah, small fish, big river. I'm hoping the uproar will have them dialing back the decision.

I feel bad because I haven't even had the boat out yet this year. It's available, I'm available but I need a day to commission it. Too many damned projects, too little time.

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