• If this is your first visit to the iboats.com Boating Forums, be sure to check out the FAQ. To post a question or comment, begin by signing up. To start viewing messages, select the forum that you want to visit from the selection below.
  • ALL iboats Forum Members and Guests:
    To show our appreciation for your participation in the Forums, we're offering an exclusive Forums-only discount good for an additional 5% off your iboats.com order for a limited time.
    To redeem, simply call our Customer Service Team at 800-914-1123 (Open M-F, 9am - 8pm Eastern Time) and mention the Forums 5% off discount. Offer excludes engines, trolling motors, and electronics.

Announcement

Announcement Module
Collapse

Help Tip: If you have a question that has not been answered to your satisfaction in the archives, it is always best to start a new thread of your own. By starting your own thread, you will receive the maximum number of views by forum members.

Below are some additional forum policies in hopes of all iboats members will follow, Thank you.

1. Please do not reply to old threads or hijack existing threads. Old threads of a technical nature are like a library book, Please do not write in them.

2. Old threads should be considered archives and used for reference only. Please do not reply to them.

3. Do not take over someone elseís thread (aka hijack) with your own question, even if it is similar. If you have a question that has not been covered to your satisfaction in the archives, it is always best to start a new thread of your own.

4. If you have a question for the original poster (OP) and the thread is over 30 days old, send the OP a PM, he may not even visit the forums any longer, or may not notice your question in the old thread.

5. By starting your own thread, you will receive the maximum number of views by forum helpers that may not even notice your question when itís posted at the end of someone elseís thread. And those answers will be specific to your particular issue.

6. Please do not post to threads that have been inactive for more than 3 months unless you are the original poster. We have very active forums and any thread that remains inactive for that long should be considered "dead". It is especially confusing when there is an entirely new question posted to an old thread.

7. Posting at the end of any thread is considered to be hijacking the original posters thread which in turn subjects the thread to be closed if it continues to happen thus not making it fair to the original poster in the future had for some reason he/she needed to return for additional information or provide an update of the problem solved which is always welcomed within a reasonable amount of time frame.

8. Please note that you should see a red banner pop up near the bottom of each inactive thread asking you not to reply to old threads. The Red banner will read: Please note this thread has been inactive for 90 days. For the best results, please start a new thread.

Thank you all in advance for doing your part in helping iboats run a smooth ship.

Additional forum rules linked below.
http://forums.iboats.com/forum-rules-guidelines-405/
See more
See less

Mercury Sport Jet 120XR Poor idle/missing?

Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts


  • Mercury Sport Jet 120XR Poor idle/missing?

    I recently purchased a 1996 Bayliner with a 120XR Sport Jet (s/n 0e189282). I did purchase a manual (Clymer) but it does not seem to relate specifically to mine since some of the wire colors seem odd and according to it, I should have an extra, large red wire coming out of the voltage regulator (which I don't). I also can't find the switch box, I assume it is the mess of wires with bullet connectors instead of an actual box.The engine used to start up and idle wonderfully, now it barely starts and only if I increase the throttle while starting. After increasing to WOT it seems to start running on all fours, but you can still hear it miss every now and then. Back down to idle works some of the time. It used to run 5000 rpm but now only does 4500-4700. (ok, ok, I miss the extra speed!)Anyways, the motor ran fine up until right around the time I replaced the spark plugs (any correlation?) I am using NGK BZ7HS-10 with a 0.040" gap (tried 0.030 & 0.035 as well). Has anyone had a problem with the spark plug wires? Can I replace them with wires I can buy at the local auto parts store? Should I be using RFI suppression plugs?Around the same time I left the blower on one night, at least 24 hours and the battery was dead. I recharged it with my truck and put it back in the boat. Seemed fine, but the voltage seemed to remain around 11.5V, around 12.5V running. If I had a bad cell in the battery would it affect the ignition?The stator is black and only has four wires coming from it, two yellow and two others whose colors I don't recall. I did a resistance measurement and one set was around 0.4 ohms and the other set was 600 ohms. Do these seem right? I do not have a DVM but do have a Fluke with a max reading indicator, but it probably reads RMS.Does anyone have any ideas? I am going on vacation next week and was hoping to take it along but don't want to risk damaging the engine if I can't get this issue resolved. I would shellout the bucks for a stator if I knew it was definitely the problem, but then again I don't think I will be able to get one in before vacation Thanks in advance for any help!Shawn


  • #2
    Re: Mercury Sport Jet 120XR Poor idle/missing?

    I have a 94 Bayliner Reflexx with a Sport Jet 90 and have also had some electrical problems. Just not the same as yours.The Clymer manual has some very detailed diagnostic steps to determine the cause of electric problems.The manual indicates that it should be started with WOT. I have had problems starting the engine and keeping it running. See my post about an electric priming fuel pump. http://www.iboats.com/cgi-bin/ubb/ul...;f=17;t=015611 It seems that the longer it sets between uses the harder it is to start. From what I have read, hard starting is almost normal for this engine.

    Comment



    • #3
      Re: Mercury Sport Jet 120XR Poor idle/missing?

      I checked again and it is the green/white and white/green wires coming from my black stator that measure 600 ohms. According to the poor manual that I have, this is way low for a black stator and ok for a red one. Can anyone verify this?Thanks,Shawn

      Comment



      • #4
        Re: Mercury Sport Jet 120XR Poor idle/missing?

        How long has it been sitting?When was last time carbs rebuilt?I know everyone blames stator for all probs on these engines, but mine was the carbs.Everytime my stator went out (twice) it just died and would never restart.Ken

        Comment



        • #5
          Re: Mercury Sport Jet 120XR Poor idle/missing?

          shawn, compression test first, and then a spark check....the color on your plugs even, or is one washed off clean? the fact that you are getting almost all your speed says you can ignore the stator...water in the fuel? a cylinder getting water in it from a bad gasket?

          Comment



          • #6
            Re: Mercury Sport Jet 120XR Poor idle/missing?

            The carbs have never been rebuilt, and it sat most of last year (stabilized and fogged). The engine ran like a top when I got it, and for a few weeks or more. The previous owner used it around 50 hours or so and kept it in great shape.I would almost feel bad if it wasn't the stator, I ordered one and am getting it friday. Maybe I can return it unopened if I solve the problem? Is 600 ohms a valid resistance for my black stator? It only has one ignition coil.The top three plugs are/were all tan colored. The bottom one was darker with some slight oil residue. I checked each cylinder with a spark tester at about 7/16" and got good blue spark while cranking.I am leaning toward cleaning up the carbs, though they look awful clean. Maybe I will pull them and clean them up while on vacation.I bought some dry gas and some carb cleaner (both STP) additive but read that their use was not recommended. Can't I use either of them? How do I treat a problem of water in the gas? I tend to think that it is not that since I have used at least one tank of gas and last time I filled it up I put in 93 octane.One last thing, when I first go and start it up, it idles (seemingly well) a few seconds and then stalls and doesn't start up and idle again. Is this a major symptom for something obvious?Thanks,Shawn

            Comment



            • #7
              Re: Mercury Sport Jet 120XR Poor idle/missing?

              Oh, and another thing, it seems to be a fairly obvious thing when it starts running 'on all fours', kind of like a switch is being thrown on and off.Shawn

              Comment

              Working...
              X