Thread: Pro785 Piston wash
07-04-2010, 10:04 AM #1
Pro785 Piston wash
I hear that the wash on a Pro785 is small. you'll never get fingernail size wash marks on the pistons..What is everyones wash look like on thier Pros? I took some pics on mine this morning.. they look ok I guess.
Whatcha think? the first is the Pto and then the Center and the Mag.
when the Pto is all the way up with like in the pic, i took my 2 fingers and can wobble the piston a tiny bit. like theres slop in the rod bearing.. just a tad.. the other wouldnt move.. although i didnt bring them up to the top like the pto was yet..
the was in the center is blocked by the light in the pic, but that one looks fine as wash goes I think. then the mag looks a litlle lean. but not too bad.
I see a couple little nickes in the piston and the head on the Pto too.. the center looks really wet and carbon dust mixed with it and the mag is fine..
any insights on this wash?
center pto and the mag on the bottom pics in that order.
the top pics are center ,mag, pto
I'm using brp8-es/'s
07-06-2010, 11:00 PM #2
07-06-2010, 11:16 PM #3
Thank you very much for posting on my thread here. thats exactly what i was looking for.. you have that nice choclate brown crown !! and the tranfer ports,intake and exhaust have the clean areas. not too big, but bigger than what I have. I'm close but not quite there..I see my crowns are black not chocolate. and the clean marks are smaller..
now I have something to go by... defineltly dont want to hole a piston on this ski! ouch in $$$$$..
I wonder why your center is all black and has big wash marks still? jetting? is that a different jet in the center?
07-07-2010, 08:37 AM #4
The CEN does have a different jet than the PTO and MAG, but they are the stock jets. Amazingly, these wash pictures were taken before I realized that the previous owner had removed the fuel restrictor from the return nipple on the center carb. The high speed screws were about 1 to 1-1/2 turns out from seated in order to give me that wash pattern.
Once I put that restrictor back in, the boat isn't topping out on RPMs due to being so rich. The screws should actually be lightly seated to 1/4 turns out. I forgot take a recent picture with how the boat sits now, but the wash pattern is much larger since I'm getting the proper fuel pressure now.
07-07-2010, 10:13 AM #5
Once I put that restrictor back in, the boat isn't topping out on RPMs due to being so rich. The screws should actually be lightly seated to 1/4 turns out.
what do you mean 1/4 turn out? on the lows?
07-07-2010, 10:18 AM #6
No, at least on the 1998, stock settings have the high speed screws lightly seated...some like it to only be 1/4 turn out from lightly seated just to be on the safe side. The low speeds should be 1 turn out from lightly seated.
Again, this is stock settings and I'm not sure how your shortened pipes and Redtops will change that.
07-07-2010, 10:49 AM #7
oh ok. i have 140's on the ends and a 135 in the center.. 1 turn out on lows, then 1.5 out on the highs.. for now.. Bob is looking for some jets for me. 1/4 out seems way to little on the highs.. but if it works , it works..
07-07-2010, 11:04 AM #8
- Join Date
- Jul 2007
- Cedar Rapids,Iowa
To me you are lean on all, I like to see a good clean wash.I'd rather run a little rich then boarder line. Because gas quality changes with each place and company you get it from. Better safe then sorry. Adjusting the needles should get you closer. You just don't want a needle 1 1/2 or farther turns out. Even if a needle is totally screwed in on a 130 jet, you are still not shutting off the jet, needles are design when fully screwed in to restrict the flow to the lowest setting for that jet,not totally close it off. Alot of guys do not mess with changing jets to the half sizes,because the needles will cover the full 5 step.
needles come every 2.5 steps. example 130, 132.5, 135, 137.5.
Bow,I sent you a PM
07-07-2010, 11:13 AM #9
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By addicted in forum Yamaha PWC Performance (2-stroke)Replies: 104Last Post: 04-28-2013, 10:47 PM
By TimAtkinson in forum Polaris Open DiscussionReplies: 19Last Post: 05-27-2008, 02:46 PM
By addicted in forum Polaris How To & FAQsReplies: 90Last Post: 01-01-2008, 02:22 PM
By TxPro1200 in forum Polaris PWC PerformanceReplies: 1Last Post: 08-10-2007, 11:57 AM
By delagem in forum Polaris Open DiscussionReplies: 23Last Post: 07-28-2007, 06:14 PM