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Discussion Starter #1
My son has a 1992 Zodiac Projet which is a 14' inflatable built around a fiberglass hull. It uses the running gear from a Waverunner 3. It weighs 660 lbs without passengers and tops out in the high 20 mph range. It leaps out of the water with its current 50 hp 650 engine/jet configuration but with 4 passengers its kinda slow.
My son has been scouring the internet looking for performance upgrades but nothing seems to be promising based on the 650 platform.
See this video to learn what boat this is
I just bought a donor ski. It's a like new 2000 gp760 with only 56 hours. It is completely stock and perfect in everyway. Compression checks out and I will do a case leakdown test before installing it in my sons boat.
Anyway's I have a few questions.



#1. Will I benefit by milling .010 or more from the stock cylinder head. I recall the 760 cylinders are port timed towards best high rpm power. Will a small compression bump give me a little more low end grunt? I will be running leaded 93 octane fuel from the marina. If it is a worthy mod what type of difference would it make? In other words will It be noticeable or worth the trouble?

#2. I haven't yet removed the 144mm pump assembly from the Zodiac so I do not know what pitch prop is in there. I will need to speak with someone with excellent knowledge on prop sizing. Will the 144mm GP760 jet pump fit where a WR3 jet pump goes? Which prop should I start out with? The GP760 is 160 lbs lighter so the prop may be to tall a ratio. However the prop in the Zodiac allows the 650 engine to reach at least 6500 rpm and tops out under 30mph. My goal is to get 35 mph with a 1000 lbs total weight. Better acceleration is what I seek the most.
Should I try to fit a 155mm pump? Has that ever been done on a WR3?

#3. While the 760 engine is out are there any worthwhile mods to do? How about those reed stuffers? Worth the $65.00?

#4. I am not sure if the stock 760 pipe will fit in the Zodiac engine bay. Will the 650 pipe fit? Will performance suffer greatly?

Here are a few pictures
 

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Really? Did I post this in the wrong section?
Gday pjv911,

Hows the engine swap going? I'm a newbie myself, just signed up so I could contact you. I also have a Zodiac Projet 420 and am considering some engine upgrades in the near future to lift performance when fully loaded.

Firstly some advice. You have asked 4 pretty full on questions there. Try one at a time in future and keep them simple as you can. I have learned this from other forums.

I spoke to a Yamaha mech a month or 2 ago and picked his brain for a while. You are probably aware by now your projet basically has all waverunner running gear.

The mech told me the 650, 701 and 760 are basically all the same 'family' and share many parts aswell as being the same external dimentions. I think the 701 and 760 have the same size exhaust ports so to use your 650 square style exhaust on the 760 you need to grab a 701 exhaust manifold from a ski that had the same square style exhaust. But the bolt holes on the 701 manifold are 8mm and the holes on the 760 are 10mm. There is not really enough meat to just drill them out so most poeple use a helicoil in the 760 bolt holes and use the 8mm bolts. This way you could keep the whole exhaust set up from the Projet as standard but run a 760 motor. But you would need the correct head to match. I think it is the 61x which has all the bolt holes on the top of the head to match the exhaust bracket holes. Not sure if you can get one for a 760. You made need to have a 701 or 650 61x head machined to suit.

Have you had a go at fitting the 760 in with its standard exhaust on? Any reports on your progress would be great. Theres not a whole heap of info out there on the Projets so lets make sure we keep sharing!!!

Good luck!!
 

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Why would some one want to help you after that stupid and dangerous video you posted. Yeah, lets give the kid who drives straight at people to just show off by seeing how close he can come to you all in the name of show off. lets give him more power to kill himself or someone else, to try and spray you :thumbsdown:.

Now I question the parent who was condoning this with a Video on You Tube???? Teach your children well lmao.

I wouldn't help you if I could. Instead of trying to hurt someone why don't you send him to a saftey course. Unless you approve of his driving style:dunno:
 

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Why would some one want to help you after that stupid and dangerous video you posted. Yeah, lets give the kid who drives straight at people to just show off by seeing how close he can come to you all in the name of show off. lets give him more power to kill himself or someone else, to try and spray you :thumbsdown:.

Now I question the parent who was condoning this with a Video on You Tube???? Teach your children well lmao.

I wouldn't help you if I could. Instead of trying to hurt someone why don't you send him to a saftey course. Unless you approve of his driving style:dunno:
Nothing like a grumpy old 'senior member' to make a couple of newbies feel welcome. Wouldnt be a forum without ya.

Thanks for your comments tho, very helpful.
 

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Discussion Starter #6
The video was found on Youtube and is not my son or anyone I know. I used it for reference only.

Why would some one want to help you after that stupid and dangerous video you posted. Yeah, lets give the kid who drives straight at people to just show off by seeing how close he can come to you all in the name of show off. lets give him more power to kill himself or someone else, to try and spray you :thumbsdown:.

Now I question the parent who was condoning this with a Video on You Tube???? Teach your children well lmao.

I wouldn't help you if I could. Instead of trying to hurt someone why don't you send him to a saftey course. Unless you approve of his driving style:dunno:
 

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Discussion Starter #7
The Projet is finished. Its an animal now and requires grab handles. I got a GPS top speed of 38mph (in 1' chop) and can run side by side with my 16' twin engine Seadoo Speedster with 220hp. I cannot say enough how great the Projet now performs.
I used all the electronics from the GP760 and added other things like Horn, Bilge pump, Bilge blower and stern light.
All Projets need the 760 upgrade!
 

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Discussion Starter #8
BTW the GP760 pipe did not fit. I used a Raider 701 62t pipe and it just fits. I used the 144mm pump and jet nozzle (required some tig welding for retaining the reverse) from the GP but bought a new wear ring and a Hooker impeller from Impros. I also modified the steering nozzle for better flow. I used a WR3 aftermarket intake grate and upgraded the pto/shaft drive hub to the larger style with 5 fingers and bigger bearing.
The muffler is from the 701 raider and is located in the rear now.
I also added a Raider hood latch.
I put a total of $3k or so into this thing but after selling off the unused parts including the original 650 engine and the remaining donor ski parts I believe I at least broke even.
I will post some detailed pictures soon.
Projet420, post a few pics of yours.
 

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Glad to hear it all went well and looking forward to the new photos.

Check out mine below. This is my first try at uploading photos so anything could happen. I had the jet pump rebuilt a few years back with a s/s solas prop put in so I will probably leave that as is, unless engine mods required a new pitch. I only really use mine to go out surfing so more often than not there are 3 of us on it with our boards as well. It still goes OK but nothing like when I'm on it by myself. I am really after more power down low when loaded than say top end speed. But both would be ideal.
 

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Discussion Starter #10
Looks like its in new condition! Very nice! Also very worthy of an engine transplant. I would like to know more about your front upholstery work. The bench seat may be too high for going fast (may loose a passenger) but the front cushion is interesting. How did you fasten them to the hull?
My son with likely use the Projet this Sunday and I plan to do some video. Right now its under a cover because the weather has been crappy all week.

Kurt
 

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Discussion Starter #11
Hey it looks like your steering cable is fastened wrong. Does it bind up when moving the hood back and forth?
 

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Fellow projeter here with plans for the 760 swap. I have an XL760 awaiting the operating table. Thanks for posting your results, and I'm looking forward to a video of the beast in action. I really love this boat and I am excited to upgrade the performance. I hope you won't mind if I post up my questions here. By the way mine is a 95 and not nearly as clean as the 2 posted here, but I am working on it!
 

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Looks like its in new condition! Very nice! Also very worthy of an engine transplant. I would like to know more about your front upholstery work. The bench seat may be too high for going fast (may loose a passenger) but the front cushion is interesting. How did you fasten them to the hull?
My son with likely use the Projet this Sunday and I plan to do some video. Right now its under a cover because the weather has been crappy all week.

Kurt
I had the drivers seat redone when I got the boat and at the same time had the front and middle seats made up. The front is held on by velcro only but the middle has a row of push studs as well. The velcro is about 2 inch wide and really does hold them on nicely but still makes them easy to romve.

My stearing is a little tight move going full tilt. I always assumed that it was because you are trying to force the bucket against all that water hammering out. At low speed its OK. But when you close the lid it does seem to pinch on the cable. Could you please show me a photo of how yours is run.

Does your one have a small wind screen on it? I have holes where some sort of wind screen was once attached but have never seen one.
 

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Discussion Starter #17
You need all the electronics to the 1200 (or 1100 if you choose). The mounting positions for both 2 and 3 cylinder engines are in all GP hulls. Its a direct swap if you have a donor ski for parts. The exhaust will swap over as well. Its much larger for the 1100/1200 engines.
Lets keep this thread on the Projet path. If you have any further questions just PM me.

Kurt
 

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Fellow projeter here with plans for the 760 swap. I have an XL760 awaiting the operating table. Thanks for posting your results, and I'm looking forward to a video of the beast in action. I really love this boat and I am excited to upgrade the performance. I hope you won't mind if I post up my questions here. By the way mine is a 95 and not nearly as clean as the 2 posted here, but I am working on it!
Good to hear from another Projet owner. Make sure you ad some photos of your boat with your questions. By the way where are you guys located? I'm in Perth, Western Australia.
 
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