Page 1 of 27 12311 ... LastLast
Results 1 to 10 of 263
  1. #1

    Talking Please Help Me With My 1996 780 SLX

    I just need help working on my 780 SLX any advice is greatly appreciated.

  2. #2
    Hi I posted this thread because I'm 100% new to jet ski's and need help with mine. It's a 1996 Polaris 780 SLX. It's in great shape but has been sitting for two years and needs work. I know alot about working on cars and motors, but this is a far cry from my drag racing days, I know nothing about 2 strokes. Basically I've replaced all fuel lines and drained gas, and right now I'm waiting on a build kit for the carbs and fuel pump. Ive added new fuel and it won't fire. I have mixed up some B-12 and marvel mystery oil and it will fire and run great on that until it burns up. I keep hearing people saying stuff about restrictors in the fuel lines???? Did I take something off and not realize it? Also I only noticed that the water separator is about a quarter full right now and thats after I cleaned it out. Should it be pulling more fuel in to there than that? Please HEEEELP?

  3. #3
    BlueFishCrisis's Avatar
    Join Date
    Aug 2011
    Medina, Ohio, United States
    Welcome to the Hulk!!!

    Get started here: Also be sure to check out the links in post #4 of the same thread as well....

    Take the time to read all of the threads posted as "Sticky" in the forum.

  4. #4
    johnsonmtz's Avatar
    Join Date
    Oct 2006
    Mt. Zion Illinois
    Think of the restrictor as a pressure regulator. It's meant to keep a little back pressure in the return fuel lines to make sure adequate fuel is delivered to each carb. In the 780 version of the Mikuni carbs the restrictor is built into the fuel return fitting on the MAG carb, so no worries, you didn't throw anything away. Those of us that own 750's have to be careful because the restrictor on those was a 1/4" diameter brass plug that was shoved into the return fuel line.

    Before you go any further, I'd strongly suggest rebuilding the carbs with those kits. Did you get the kits from John Zigler? The only reason I ask is he provides a kit that contains only the parts necessary for Polaris skis. If you order a generic Mikuni 38 kit you'll get all kinds of diaphragms and gaskets that are meant for carbs that have the fuel pump built into them. Also, John includes new needles and seats in his kits.

    Rebuilding the fuel pump isn't a bad idea, just be careful when you install the check valves. There are little black rubber mushroom type plugs that are used to hold the check valve in place and they are installed by pressing them through the hole. It's very easy to puncture that plug as you install it. if that happens it's trash and you need to get a new plug.

    Under normal operating conditions the water separator should be completely full with no air gap. After you do all the carb work I would first spray some fogging oil in the plug holes and down the carb throats. Remember, there is no crankcase oil so until there is fuel flowing there is no lubrication for the crank bearings. Now, with the plugs removed hit the start button in about 10 second bursts and resting for 10 or 15 seconds between (we don't want to burn up the starter). After several rounds of this you'll see the bowl fill up quickly and start to send fuel through the lines. You might also spray some fogging oil in the carbs every couple of cycles just to make sure the bearings have lube. The trick here is having the plugs removed eliminates pressure and allows the motor to turn faster on the starter.

    Good luck and keep us posted on your progress.


  5. #5
    Thank you guys for the advice. So far I've replaced all fuel lines, about to re-build the carbs/fuel pump. I by passed the fuel cut off for this season and plan to replace it this winter, I also blocked off the oil pump and taped my oil float up and left the tank in as my fuel separator bolts to the side of it. I also deleted the pop off valve and thermostat because it looked like crap. I don't really know how this will affect my ski but I live on the coast in south Texas so in riding season the water temp is about 80 and outside is around 90 or so. Yes "johnsonmtz" I have heard of John Zigler in fact I just ordered my fuel pump re-build kit as well as my needle and seat from him, I wish I had found him before I ordered my carb kits. I think Zigler and his fine establishment are excellent and gave me the best service I have had in a very, very long time. I spoke personally with him on the phone and it made me sick that Wal-Mart has driven lots of small businesses like Ziglers out of business. Most people now a day’s don't know what it is like to walk in face to face and buy something from a guy you see every day and live in the same town with; makes me sad. What do you think about me taking the thermostat off? Can someone please tell me how to read Piston Wash!!!! I'm so confused, do I even need to worry about this as long as I set my carbs back the way the factory says, if anyone can post a pic of exactly what the perfect wash looks like that would be awesome. If I do have to check it can I just shine my super bright flash light in the plug hole (420 Lumens) or do I have to pull the head. Thanks for the help guys.

  6. #6
    Ok, I started re-building my carbs and they were surprisingly easy. I have done plenty of Holley, and Quadra junks over the years so I was expecting this to be not very hard but still happy to see the simplicity. Still waiting on the needle and seats to finish them. I'm not sure how to set the carbs, I have plenty of info on the stock setting but still not sure how to tell if it's right or not once I've got it running again. Truth be told I'd like to run it slightly rich for safety, I'm not real worried about the small power loss or needing to clean plugs more often.

  7. #7
    BlueFishCrisis's Avatar
    Join Date
    Aug 2011
    Medina, Ohio, United States
    Most guys here will say to start with stock settings + 1/4 turn open to try and stay on the rich side. Once you have some run time, your piston wash seems to be the desired method to check actual running conditions.... Search Piston Wash in the threads.... there is plenty of info and pics to get you educated.....

  8. #8
    Okay well....... bad news. I actually did what you said without seeing your post and fattened up the motor and guess what? I toasted the PTO piston and scored the sleeve some. I was riding with my wife for about 30 min and everything was okay, I then dropped her off at the dock and when I started up it was hard to start and didn't wanna go but I gunned it and it took off and I ran about for about 2 min and then did a speed run that ended in some nice piston slap and then a dying engine lol. To make things worse I was in the ocean and had so swim the damn thing back to shore luckily it was in the back back and wasn't choppy. I did lose my freaking wedding band though treading water. I can't believe that that piston was lean for 30 min and lasted that long but hey maybe because the piston didn't blow up it was just chipped away around the edges. Either way my thoughts are to bore the whole ski 1.0mm over and put it back together.

  9. #9
    Banned User
    Join Date
    Jun 2010
    Milwaukee WI
    Did you do a leak test on the engine before running it? Make sure you have no air leaks when you reassemble it this time around. That can lean out a cylinder and burn it up.

  10. #10
    No; I'm not really sure how to do a leak down test. What do you think about my situation though? If the PTO was lean enough to burn up don't you think it would have happened before 30 min of hard riding? Thanks everyone for the advice and help, this site is awesome!

Page 1 of 27 12311 ... LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. FS 1996 slx 780
    By TBone14 in forum Polaris Skis
    Replies: 5
    Last Post: 07-27-2011, 10:10 AM
  2. Help with SLX 780 1996
    By cubajorge2008 in forum Polaris How To & FAQs
    Replies: 1
    Last Post: 06-25-2010, 11:32 AM
  3. Need help with a 1996 polaris SLX 780
    By clint rogers in forum Polaris PWC Performance
    Replies: 10
    Last Post: 08-12-2009, 01:57 PM
  4. 1996 slx 780 help
    By Robert L Neely in forum Polaris Open Discussion
    Replies: 3
    Last Post: 08-22-2007, 11:02 PM
  5. 1996 slx 780 help
    By Robert L Neely in forum Polaris Projects
    Replies: 0
    Last Post: 08-21-2007, 05:09 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts