Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 26
  1. #1

    2003 MSX 140. rough running issues. Temp related?

    A customer bought in a 2003 MSX 140 (32 hours total time with some salt water use) for repair. The engine refused to run above 3000 rpm without misfiring and cutting in and out. (It had run correctly and smoothly for several hours the day before.)
    He had taken it to a dealer who said the fuel pump was bad and sold him a new fuel pump assembly. He did not want to install the pump "to busy" he said. So I took on the job and found out why he did not want to install the pump! It took me darn near two days and required taking the handlebars and steering mechanism out! ( Old pump motor did seem to be bad and would not run on the bench with power applied ) Anyway, with the new pump installed fuel pressure at the injector test point was 25psi and motor ran well out of the water on a hose.

    The customer also said that he thought the "hot engine" message was displayed when the motor started playing up so I took the pop-off valve/thermostat assembly apart. I cleaned the components and tested the thermostat which was opening at 82 degrees C instead of the 62 degrees the manual says it should open at. To water test the ski I assembled the pop-off valve assembly without the thermostat installed. (Lake water temp is around 85F around here so I don't think the engine running to cool is an issue). I checked the water inlet screen was clear and I also checked that the water injector oriface on the exhaust was clear as well. I did notice quite a bit of corrosion around the engine and the bolts holding the pop-off valve assembly together needed intense heat to get them out.

    Took the ski out for a test run yesterday. 10 minutes of running at low speed in the no wake zone with no problems. Then opened up to around 3/4 throttle, the engine run cleanly for around 30 seconds and then started misfiring and cutting in and out and the "hot engine" message came on momentarily. Throttled back to idle and engine idled perfectly. Tried opening up again numerous times and the same results. Initialy runs smooth for a few seconds and then misfires/cuts in and out. No more hot engine message though and no bangs from the exhaust as if the ignition is going on and off.

    Any body have an idea as where to look next for the problem? Engine runs cleanly below 2750 rpm. I'm sure the engine is not running hot and it does not feel hot. (No thermostat in it remember). If it is a computer problem surely it would not run cleanly for a few seconds before misfiring? Wouldn't it just run badly above a certain rpm all the time? Could the temp sensor be faulty and be telling the computer it is getting hot and the computer is going into "SLOW" mode when the throtlle is opened up and the sensor warms up? It did seem like the longer I let it idle the longer it would run smoothly before misfiring.

    Although an experienced marine mechanic this is my first time working on a Ficht DI Polaris so any advice would be appreciated.

    Thanks.


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    36,589
    +1
    1,275
    Welcome

    Where are you located?

    Check the cooling water flow through the EMM itself. That water flows first through the flywheel cover, then through the EMM, then exist at the hull exhaust fitting. Check for kinked hoses, clogged elbows at the flywheel cover, or a crushed/kinked exit hose. The water path

    If the EMM has been starved for cooling it can cook itself and become unstable, sometimes with weird symptoms.
    Inside the EMM is a straight water tube, should be able to see daylight through it.
    On my own MSX 140 I now have a single exit pisser to let me monitor the water flow out from the EMM.

    Other areas to check are the temp sensors on the exhaust pipe and the air intake base. Check for correct ohms, physical cuts, or wire chaffing.

  3. #3
    Thanks for the help. I am located in central Virginia. I have checked in the manual and found the resistances for the temp sensors and will check those out along with all the cooling water hoses and pipe work. I did not realize how important the cooling of the EMM was. You gotta love electronics!
    Slightly on the same subject I think it's time I bought my own computer diagnostic equipment as I have had a lot of jet skis and outboards to work on this summer. Even the ski boat inboards are full of electronics now and as we will only see more electronics on marine engines (even diesels) I think investing in a good diagnostic kit would be a wise investment.
    Any suggestions? I have been looking at the "Scanworld" system. http://sws1.com/scanmarine.shtml
    No anything about this product?

  4. #4
    Banned User
    Join Date
    Jun 2010
    Location
    Milwaukee WI
    Posts
    16,708
    +1
    1,324
    Check the temp sensor in the exhaust manifold. There was a bumper update that helped relocate the plastic exhaust tube further from the manifold. The plastic exhaust tube would rub the wire on the sensor and wear it through. That was exactly the problem on mine when i bought it. I would be willing to bet that update has not been done on your ski.

  5. #5
    Thanks for the info. Was the bumper update a service bulletin ? If yes is there a copy of the SB on the Internet somewhere?

  6. #6
    Banned User
    Join Date
    Jun 2010
    Location
    Milwaukee WI
    Posts
    16,708
    +1
    1,324
    Yes it was a service bulletin

  7. #7
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    36,589
    +1
    1,275
    Quote Originally Posted by BryanP View Post
    Yes it was a service bulletin
    Do you have the bulletin number?

  8. #8
    Update.
    I removed the water temperature sensor today and found that the sensor was open circuit. It should have a resistance of 985-1010 ohms at 25 degrees C. So one can assume that with no input from the sensor the EMM had no idea what temperature the engine was running at and went into "SLOW" mode. I also checked the air temp sensor and that has a resistance of almost 1,000 ohms where as it should be between 990-110 ohms at 25 degrees C.
    I have ordered two new sensors and when I have installed them I will write again and let you all know if that solved the problem. Interestingly enough the dealer had run a diagnostic check on the engine and did not find the failed water temp sensor just an overheat code. Maybe he did not run the diagnostics correctly? Another good reason for me to get my own diagnostic equipment I think.
    As I had already removed part of the exhaust to get the water temp sensor out I checked all the coolant hoses and fittings for blockages etc. I also took the EMM out and checked the water cooling passage. Everything was clear and OK.

  9. #9
    Banned User
    Join Date
    Jun 2010
    Location
    Milwaukee WI
    Posts
    16,708
    +1
    1,324
    I am 100 percent sure that exhaust sensor was the problem. Now buy this and install it....


    http://www.ebay.com/itm/190625771818...84.m1423.l2649

  10. #10
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    36,589
    +1
    1,275
    Quote Originally Posted by BryanP View Post
    I am 100 percent sure that exhaust sensor was the problem. Now buy this and install it....


    http://www.ebay.com/itm/190625771818...84.m1423.l2649
    Polaris OEM PWC Exhaust Tube Temp Sensor Bumper/Spacer Kit for MSX 140

    Polaris 2202780

    Click image for larger version. 

Name:	image.jpg 
Views:	97 
Size:	65.0 KB 
ID:	309734

    So post up the instructions and the parts size info so we can make our own!

Page 1 of 3 1 2 3 LastLast

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. 2003 MSX 140 stopped running, has no spark, EMM was repaired
    By Nathan87 in forum Polaris Open Discussion
    Replies: 2
    Last Post: 04-06-2016, 04:17 PM
  2. 2003 msx 140 runs rough while giving it the throttle.
    By dcspankie33 in forum MSX/Matrix
    Replies: 6
    Last Post: 09-02-2014, 09:29 AM
  3. 2003 MSX 140 got water in tank now throttle issues
    By SplishSplash in forum MSX/Matrix
    Replies: 2
    Last Post: 08-09-2013, 07:33 AM
  4. 2003 MSX 140 Issues
    By airframe89 in forum MSX/Matrix
    Replies: 3
    Last Post: 01-28-2013, 09:35 PM
  5. 2003 MSX 140 -won't stary running
    By Scott M in forum Polaris How To & FAQs
    Replies: 7
    Last Post: 01-17-2012, 12:09 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
  •