787 Water Outlet

[DWJet]

Good Day

This is my first post after purchasing a jet boat with a 787 Seadoo motor in it, so firstly thanks for having me.

My question is where the valve/tape is coming out of the engine should this be connected someplace? or should it always be closed?

Thanks
Darren

 

[etemplet]

I don't know why a valve would be there in the first place but I'm not a boat guy. On the jet skis that line connects to a fitting that discharges out the back of the ski.

 

[DWJet]

I don't know why a valve would be there in the first place but I'm not a boat guy. On the jet skis that line connects to a fitting that discharges out the back of the ski.

Thanks for the reply, when you say a fitting would it be a control valve or straight out the back with no regulation ?

 

[etemplet]

Thanks for the reply, when you say a fitting would it be a control valve or straight out the back with no regulation ?

On the skis there is no valve in the line. It is routed out the back. That line would be used to back flush the cooling water system on the skis.

I'd looked for a diagram to see where the hose runs to because boats can be set up differently. I found this picture on a 1998 Speedster which may not be your ski. Looks like what we see on the jet skis with the 787 engine. Follow the arrows. Good Luck !!

 

[DWJet]

On the skis there is no valve in the line. It is routed out the back. That line would be used to back flush the cooling water system on the skis.

I'd looked for a diagram to see where the hose runs to because boats can be set up differently. I found this picture on a 1998 Speedster which may not be your ski. Looks like what we see on the jet skis with the 787 engine. Follow the arrows. Good Luck !!

View attachment 60906

Thank you very much, will have a look over it.

Thanks
Darren

 

[Spider4real]

That does not appear to be a seadoo hull. Looks like someone took the motor and electronics out of a ski (not a boat) put it in a custom boat hull. So whoever build this thing made some changes to the setup.

In any case, everything etemplet said was correct for boats as this is how my 96 challenger was. But I am not sure what happens if you block that line with a valve (ski or boat). I would think it would drastically reduce water flow and not cool the engine as well. The water needs to get out. Less water going out would mean less water going in (this purely my rationale) Unless there are other mods on your boat that compensate for this somehow.

 

[rusty nail]

Here is the cooling system and how it functions.

Attached. file

 

[DWJet]

Here is the cooling system and how it functions.

Attached. fileView attachment 60907

Thanks very much for this I got everything running good all the above info.

Thanks

 

[GeoSpo]

I'm pretty sure the previous owner modified that line for either a simple engine flush via the internal engine bay, or to winterize. I'm guessing that's the reason for the valve. I live in north Idaho and have a 96 & 97 GTX and need to winterize my skis with 50-50 antifreeze flush.