moving the jet pump and intake back

[rbtlen]

Is there any benifit/problem with moving the jet pump and intake back farther towards the transom? I have a 96 voyager 15' jet boat. It origianly came with the 120 sportjet setup. The sportjet didn't come with the boat as it was junked. I bought the boat for 100.00 and most everything is there exept the pump and motor. I know that you can install the newer sportjet pumps and motors but I was considering a different route. I am thinking about installing a different style pump like some of the yamaha/seadoo boats have but powered by a small ford zetec or subaru flat 4 driven off of a belt drive. I have read moving the motor as far back would be best on the smaller jet boats since they don't usually have alot of power. I had considered the subaru since it is all aluminium and could possibly mount it over top of the pump turned around with the bell housing to the front and driven off of a wide coged belt. That is if there isn't enough room to mount it in the conventional style that the berkley/jacuzzi pumps are set up with the motor infront of the pump. That may create space problems. But if I could move the pump and intake back in the boat than I would have more room to mount things. I don't want to have to much weight towards the front. Basicaly I will set it up anyway that it needs to be.

[jim lee]

I donno' how your setup is but..

If you go to a Drag race and look at the setups for the jetboats, they -all- have as much of the pump sticking out the back of the hull as possible.

The pumps are typiclly moved back 'till the intake hole is abut an inch or two from the transom. This is so some matrial is left strapping the bottom of the boat togather behind and under the pump.

Why do they move back the pumps? When your jetboat's at speed, the intake must be in the water. The further forward this intake is mounted, the more boat is dragging in the water behind the intake.

I.E. At speed, the intake and ride plate are pretty much all that's touching the water on these machines.

Good luck!

-jim lee

[speedboats]

Moving the unit back is a definate speed advantage. Using the boxer 4 or 6 from Subaru will mean you could place the engine over the pump and still maintain some level of COG. One thing to be aware, the jet-ski type jet pump requires to revved reasonably high when compared to the Subaru, if you are using a belt then this would be an opportunity to 'gear' the jet to spin faster than the motor.