05-07-2015, 08:09 AM #1
Can I shim a spark nozzle to get more bow up
I looked around a bit and did not find anything on GH about this. (it could be out there but I missed it)
Anyone have any experience permanently shimming the exit nozzle on a spark (or i guess any other sea doo) to get more bow up.
We have the engine in another application and are looking to bring the nose up a bit on the boat to help with high speed steering. Boat is running very flat with lots of hull in the water. Anyone have any experience or reference to this? I have not dealt with custom modifications on any of these products before as we just tend to you off the shelf and stock components on our builds.
Looking for any guidance. (please note no room for vts etc.) this would be on stock spark pumps with manual reverse bucket packages installed.
05-07-2015, 08:44 AM #2
- Join Date
- Jul 2007
- near Toronto, Canada
What you are looking for is often called a 'pump wedge' that fits just in front of the jet pump main exit nozzle. The wedge changes the exit angle of the pump and forces the rear downwards, causing a lifting effect at the bow.
I do not know if there is an exisiting pump wedge for the SeaDoo Spark.
If you cannot find what you need, the advent of 3D printing makes it possible to have them custom made. And you can experiment with the amount of angle to find the optimal combination for your hull.
05-07-2015, 09:01 AM #3
thanks k447. I have also heard reading another forum about some guys spark porpoising that you can switch the venturi from bow down position to bow up position by changing or swapping the bushings? He referred to part 710 and 720 I think.
I have a full pump assembly in the shop right now and was going to take a look at it.
05-07-2015, 03:22 PM #4
05-07-2015, 03:49 PM #5
Mine came in the bow down position (3up ski). Tried both ways, does make a diff.
05-08-2015, 07:07 AM #6
Refrence comment 53 by Water Pig
Is that what you where talking about (only flipping it for bow up)
As Water pig has olbviusly done this might wanna shoot him a message.
05-08-2015, 09:06 AM #7
Yes, that is what I was referring to. It seems as thought the few packages we have gotten have the bushing turned into a bow up position from the factory. I took one in the shop apart yesterday just to see how it worked and it seem flipping it 180 does in fact give it some down angle. Unfortunetly I am looking for some up angle.
Stock it seems as though its at a "level" angle and can only really be adjusted down. Not up...unless I am missing something.
05-08-2015, 10:31 AM #8
That is true ... reversing the bushing 180 only provides a down bow or basically level...
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