Thread: Pro 785 Water Routing
10-24-2006, 05:48 AM #1
Pro 785 Water Routing
I and starting with a clean slate and putting together a shoping list. What is the best water routing for a 785 I need check valve cracking psi and orfice sizes.
10-24-2006, 02:16 PM #2
Hope this helps. It's for 97 & 98
10-24-2006, 03:25 PM #3
Thanks I have that and the 99 2000 routing and was woundering what is the best routing as I can do it any way that is best. Or if there is a better aftermarket way that is better.
10-24-2006, 10:37 PM #4
Here is a little Polaris history lesson.
Darren Hedlend left Polaris for Riva and did not do the final tweaks on 'his 785 project' before final production
The testers found that with the water routing set up like it was suppose to be (from chamber body to stinger with pisser out from the stinger) that if the ski was tilted up (as in steep boat ramp) after idling for a while the water in the pipe would pour into the engine thru exhaust.
Not good. This was one of the things holding up production of the pro785.
So without Darren around some braineac thought up this complicated restrictor water feed system for the stingers.
This system did stop the water from draining back into the engine.
It worked somewhat until you mod and change the water pressure in the system. Then all the restrictor sizing goes out the window.
O-ring head was enough to change water flow to the stingers. Sometimes even a prop change would do it.
I mean it was very sensitive to water pressure change.
The 785pro had great over-run rpm if the stingers were flooded with the right amount of water. With the restrictor system, stinger water was never consistent
After working with some friends at Polaris to try and rectify this problem, the only answer was to rout the water from chamber body to stinger and not to idle it at all before pulling ski out on steep ramps and hope no water drained back into the cyl. I did not like this since on a beach dolly it was way too easy to tip the front up and drain the pipes into the cyl.
If you came in to the beach hot and cut the motor before it had a chance to idle you might have a dry pipe. If you restricted the water to the stingers to avoid this than over rev rpm were down.
No one at Polaris knew about jetworks back then.
Well I saw a jetworks valve in one of the jetski magazines being advertised for the seadoo.
Seemed like it would be perfect for the pro785
I ordered 3 and rerouted the pipes like they were suppose to be as in the diagram but with a jetworks inline. Man it worked good like that.
I talked to the guy at jetworks and told him about the problem Polaris was having with the pro785 stinger water and how his valves fixed the problem perfectly. I also talked to my buddy at Polaris and told him about jetworks, he was very interesed.
Well, next year the pro 785 came with jetworks valves
Last edited by allcool; 10-24-2006 at 11:04 PM.
10-24-2006, 11:37 PM #5
I just LOVE when you get to hear a little Polaris Camp history.
I finally mounted my 46's to those manifolds I got from you, I'll be running my SLTX this weekend.
So uhhhh................you care to reveal the brainiacs name???
10-25-2006, 05:43 AM #6
10-25-2006, 06:04 AM #7
No thermo, you already know that.
For the stingers, feed a 3-way tee from the water flute with it's own 3/8" line. Water from flute, to one 3/8" flow control, to tee, to stingers. It's the new school way.
I know you're looking for specifics, I'm working on it.
10-25-2006, 06:17 AM #8
10-25-2006, 10:32 AM #9
After Darren left, took a little while to get the project back up to speed. Don't remember any names of who took over the pro785 project
I do know that Chris Bush from the Polaris pwc test center in Fl, back in the day, was a Genius on these 2-strokes and props.
Polaris was lucky to have this Mercury Marine guy.
Chris was/is the Polaris impeller/prop guru. He is the one that started me out kicking props. Chris would know who was responsible for the original water routing of the pro785.
Or if he doesn't, then Dallas might know.
Glad the manifolds are working out for you.
I got more polaris parts, going to list them soon.
10-25-2006, 10:35 AM #10
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