Announcement

Collapse
No announcement yet.

no midrange 95 SL750

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    Re: no midrange 95 SL750

    no matter what temp... As a mtter of fact, I removed the thermostat and stuff to help cool it down. Made a big diff. in the engine and rail temp.

    I talked with my watercraft mechanic instructor today, Dale Swanson, and the first thing he asked was what are the flame arrestors like. Sure enough the last dude replaced them with after market Ocean pro's and doesnt look like he increased the jet sizes. All that new air is why it is running sooo lean and choking down 25% fixes it up. The quick fix is to replace with a stock arrestor or new jets. He also said the 94 model has the return fuel line restrictor built into the rail, not in the hose. I did not replace that hose anyway but I dont believe it has on in it.

    fwiw

    Jim

    Comment


    • #17
      Re: no midrange 95 SL750

      Well, as of this writing 6/17/05, I have replaced the Flame arrestor back to stock for a quick and simple comparison. Cannot tell any real difference. Problem still there. Next I suppose I will go research the restrictor part. I researched it on partsland.com website and they DO show it installed on the 94 model.

      Comment


      • #18
        Re: no midrange 95 SL750

        Checked return line and verified there is a restrictor installed and restricting. I suppose the next step is to pull the carbs and inspect...

        Comment


        • #19
          Problem Found-Damage already done.

          Pulled carbs today. Found #3 valve and seat completely plugged up with some kind of greenish looking varnish, probably gas/oil mix dried up,

          Just for the ske of completion, I took compression readings. #1- 145, #2-145, #3 000000!

          Was able to pull #3 cylinder/piston without removing the rest of the exhaust manifold. Piston had halve of the crown missing.
          Can I reassemble in the reverse manner without pulling the exhaust and manifold?

          Jim

          Comment


          • #20
            Re: no midrange 95 SL750

            also, do you have the add-on or bigger fuel pump?

            Comment


            • #21
              Re: no midrange 95 SL750

              3 output..780 pump

              Comment


              • #22
                Re: no midrange 95 SL750

                welp, guess that carb cost you a piston. Sorry to hear, glad you found it, hurry back to the water ! :)

                Comment


                • #23
                  Re: no midrange 95 SL750 Update

                  Well, after replacing the #3 piston (top corner broken off down to the rings) and recleaning all three carbs (new needles and seats too, 2 out of 3 where leaking) Took out, carefully broke-in. Carbs carefulllly adjusted according to spec. Put on STOCK flame arrestor, Ran Great!, Real crisp, Gave to customer, told him to be easy for a tank or 2 to break-in.

                  8 hours later, died, wont start. No compression in #2, removed, nice lill hole in piston.
                  Am I missing something here? Carbs are perfect. Adjustment is factory spec. Oil pump seems to be working, hard to tell if working on all 3 I suppose. Could there be a timing issue with a sliped or torn woodruff key? Can I check with engine in ski? I suppose for $15.00 I should go ahead and eliminate the oil pump but I hate to rely on a customers ability to premix.

                  Comment


                  • #24
                    Re: no midrange 95 SL750

                    The only things that put holes in pistons are - air leaks, lack of fuel, and too hot spark plugs. Air leaks on the center cylinder are almost unheard of.
                    Last edited by Technical Support; 07-07-2005, 08:53 AM.
                    SBT Tech Support is here to help with your problems.
                    We try to answer each question quickly and accurately.
                    Please do not use Private Messaging for Tech Support, use the forums.

                    Comment


                    • #25
                      Re: no midrange 95 SL750

                      Well if it's not the timing or the crank that is certainly good news. Sounds like a block-off kit and increasing the mixture to 1 full turn out insted of 1/2, run a bit, read the plug. then slowly take back to 1/2. Do you agree?

                      The customer did change the plugs to BPR6es after he had trouble getting it started but that was after the fact I beleive. I have put the 7's back in.

                      Comment


                      • #26
                        Re: no midrange 95 SL750

                        Most of the time the simplest explanation is usually the right one. I would bet those 6's made their way to the engine sooner than you think.
                        SBT Tech Support is here to help with your problems.
                        We try to answer each question quickly and accurately.
                        Please do not use Private Messaging for Tech Support, use the forums.

                        Comment


                        • #27
                          Re: no midrange 95 SL750

                          well...... I removed #3 today to get #2 piston out and #3 is also on its way out. It's crown is melting away down to expose the rings at the locating pin.
                          Does this sound simply like lack of lubrication? The jets are set at factory. #2 piston melted nice dime size hole, #3 is melting the edges away (blowby?) #1 looks good.

                          On another subject, when I removed the cylinders, I noticed that the water jackets below the cylinders in the lower case look completly dry and a little corroded. I did some investigating and it doesn't appear to me like there is any way water can get down there. Is this right? The water jackets in the cylinders DO NOT connect to the lower case water jackets! The lower case has the 7/8 "T" and the other nipple coming out and it appears from all the lit. I've read that you simply plug them off. It is possible that the upper and lower case came from a different year than the rest of the ski so maybe the plumbing is not right. Any takers???

                          Comment

                          Working...
                          X