Seadoo GS 717 to 787 Upgrade

[etemplet]

My apologies but I don't have the forum search button on my browser for some reason but I'm curious about installing a 787 in a GS model that is set up for a 717. Over the years I have read about installing larger engines. I just want to see the amount of work involved to mount the 787 engine securely long term.

I have a GS that I am going to restore and I recently removed a good 787 from another ski. I have all the parts I would need.

 

[mikidymac]

I don’t feel it’s worth the effort.
You would have to fabricate engine mounts since the 720 uses 4 and the 787 uses 3.
I was never a fan of the GS/GSX hull.

 

[etemplet]

I'd like to see how someone did it. I'm curious what they might have done with the fiberglass and how they secured the mounts to the hull. Did they use the current mounts as an anchor point? Not that I can't do it why break new ground when it isn't necessary. I have a 787 I don't need so I'll save $1000 on an engine. Just checking into it. Might be fun.

 

[etemplet]

Find a little tib bit on the forum.

Thread '717 to 787 upgrade and motor swap'

Oct 10, 2016

I have a 717 which needs a new top end...and possibly bottom as well.

I would like to put in a 787 in it's place. On other previous posts, I have read both that it is doable and that it is not.

Things to consider.

Motor mounts
impeller drive shaft
pump
electrical
room in the bilge. ( I have enough room)

Please lend your experience here.

THANKS!!

• Armysinger
• Replies: 5
• Forum: 2-Stroke Sea-Doo PWC Forum

 

[lagojaguarasp]

I don’t feel it’s worth the effort.
You would have to fabricate engine mounts since the 720 uses 4 and the 787 uses 3.
I was never a fan of the GS/GSX hull.

I pathetically flipped my GS today on its first-ever two-person ride—my first flip ever. I was just idling in a slight turn, trying to dock, and it just rolled over with no warning.

So in your opinion, does the GS/GSX hull fall between two stools? As in, it's not playful enough to be like an X4 or a '97+ XP, but not stable enough to be a safe two-person cruiser like a GTI?

 

[mikidymac]

I pathetically flipped my GS today on its first-ever two-person ride—my first flip ever. I was just idling in a slight turn, trying to dock, and it just rolled over with no warning.

So in your opinion, does the GS/GSX hull fall between two stools? As in, it's not playful enough to be like an X4 or a '97+ XP, but not stable enough to be a safe two-person cruiser like a GTI?

That basically sums it up.
For me the GSX isn't playful and fun like a X4 or 97+XP and not as stable as a 3-seater. It is better in rough water than a X4 but not as good as a 97+ XP or a 3-seater. IT does have a large fuel tank so there were people that used to use it for endurance racing back in the day before 3-seaters became the go to.

 

[etemplet]

I pathetically flipped my GS today on its first-ever two-person ride—my first flip ever. I was just idling in a slight turn, trying to dock, and it just rolled over with no warning.

So in your opinion, does the GS/GSX hull fall between two stools? As in, it's not playful enough to be like an X4 or a '97+ XP, but not stable enough to be a safe two-person cruiser like a GTI?

I really like the GS hull. They are very fun and more stable than the XP or SP. I like the size also. When you rolled yours over that has been my experience, low speed in a gentle turn and they just roll toward the back. I think the correct response to that moment is to gun the engine. That only happened to me twice but the ski never flipped over. I was able to ease it back into compliance. LOL

I'm not a XP fan. To me it is more like a dirt bike and you really need to hang on. The XP can be unstable at speed as well. As with anything you give up performance for stability. Congratulations to Seadoo for developing such a wide variety of well performing jet skis.

On a side note, the GS doesn't need a 787 engine. They are plenty fun with the 717. They are NIFTY.