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VinylImagesInc

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PostPosted: 29 Jun 2016, 16:50 
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Joined: 02 May 2014, 23:35
Posts: 113
look some of you guys have great ideas on this forum and when a question is asked you usually redirect to someones build could some one pose me a pic or two for spooning the underside of an inboard jet if you could provide measurements or little tricks to install one please need help with cavitation .


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PostPosted: 29 Jun 2016, 21:25 

Joined: 30 Nov 2015, 23:25
Posts: 17
Location: jarretsville md
I have just starred to make a spoon for my jet jon after having some pretty bad cavitation problems. I don't know If my design is the right way of doing it or not


20160629_205051.jpg
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PostPosted: 29 Jun 2016, 21:31 

Joined: 30 Nov 2015, 23:25
Posts: 17
Location: jarretsville md
I started with a 4ft × 2ft .90 thick pice of aluminum made the top a hair wider then my intake 6 1/4in. Then I clamped one side of sheet all the across on a table and bent 3 3/4in to slope my sides down to a angle I was happy with


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PostPosted: 29 Jun 2016, 21:37 

Joined: 30 Nov 2015, 23:25
Posts: 17
Location: jarretsville md
I still need to finish the front ramp part of my spoon. Having a hard time finding a perfect way to get a nice gradual front slope along with having being a spoon shape in the front


20160629_204721.jpg
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PostPosted: 30 Jun 2016, 17:00 
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Joined: 02 May 2014, 23:35
Posts: 113
looks good i was kind of thinking the same thing just wasnt sure how long to make it


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PostPosted: 30 Jun 2016, 17:36 

Joined: 13 Nov 2014, 08:01
Posts: 666
I too had cavitation problems with jet ski insert flush with jon boat hull.

I dropped the jet ski insert to about 1-1/2 inches below hull. It is level along it's length.

For the transition, I used the material that was cut out of jon boat (for insert).

It is about 4 foot long, so it has a gentle taper. Since my old mig welder hates feeding aluminum wire, I just tack welded it in (at least 100 tacks!)). I used epoxy resin & fiberglass cloth to seal it up. So far, leak free.

Performance wise, I can run in 2 inch chop & no cavitation, so it was worth all the work.

Edit: I also re-shimmed the pump mount. so as to keep the thrust angle similar to before. (this was no small task either).

new bottom 002.JPG
new bottom 002.JPG [ 68.56 KiB | Viewed 2471 times ]


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PostPosted: 04 Jul 2016, 18:58 

Joined: 30 Nov 2015, 23:25
Posts: 17
Location: jarretsville md
I was able to some work making my spoon I was wondering what you guys thinks so far if I'm heading in the right direction


20160704_175200.jpg
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PostPosted: 04 Jul 2016, 19:03 

Joined: 30 Nov 2015, 23:25
Posts: 17
Location: jarretsville md
I only have one side of intake tac in right now still have a lot of work with smoothing everything out


20160704_175114.jpg
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PostPosted: 04 Jul 2016, 22:15 

Joined: 13 Nov 2014, 08:01
Posts: 666
Bx - Your spoon looks much like the one I built. Should work great. Hope you have a good welder, those are long weld joints!

BTW, the steering response on my JJ is now heavier than before. Probably shouldn't be a surprise. It's not terrible, but definitely not as fast of response compared with the flush intake.


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PostPosted: 04 Jul 2016, 23:05 

Joined: 30 Nov 2015, 23:25
Posts: 17
Location: jarretsville md
I have a 200 miller spool gun welds pretty nice I was definitely going to weld the whole front down and grind it smooth for a nice transition I was thinking about laying a couple 3inch welds down the sides and flex sealing rest of the sides less welding less chance of having leaks also I'm worryed about the angle of intake seems to be a little steep ( not angle of the spoon intake ) I was never able to get my boat to go over a quarter throttle before it spin the pump or lose prime which I found my jet unit was leaking outside boat which means it must been sucking air sence it wasn't totally sealed


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PostPosted: 04 Jul 2016, 23:12 

Joined: 30 Nov 2015, 23:25
Posts: 17
Location: jarretsville md
I made my aluminum intake almost exactly like the fiberglass tigershark intake


20151229_210941.jpg
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PostPosted: 04 Jul 2016, 23:18 

Joined: 30 Nov 2015, 23:25
Posts: 17
Location: jarretsville md
Kinda hard to see in this picture my jet is level coming out of the boat and I also have a trim nozzle


20151230_174406.jpg
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PostPosted: 05 Jul 2016, 13:03 

Joined: 13 Nov 2014, 08:01
Posts: 666
I se what your intake up-angle concern is & I think it valid. If not too late, i would start the transition much earlier. If you could put a radius on the spoon (sideways) that would be a bonus. The water wants to follow a curve.

I did most of the forming of my spoon with stacked/screwed together lumber & bouncing on the sheet to get it to form. I also fab'd a brake press, but it was limited to short section.


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PostPosted: 05 Jul 2016, 15:08 

Joined: 30 Nov 2015, 23:25
Posts: 17
Location: jarretsville md
Now if my boat runs and moves at like a 1/8 thottle with out cavaition does that still mean my intake ramp my be a little to much of a angle or is that all air bubbles getting into pump related. It loses all prime when it seems to get ready to get on plain


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PostPosted: 10 Aug 2016, 19:16 

Joined: 30 Nov 2015, 23:25
Posts: 17
Location: jarretsville md
I have some more time to work on my spoon design
and I almost got done


20160810_190934.jpg
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