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  1. #1

    MSX 150 Trouble starting when warm after 15 minutes or more also limp mode issue

    Hi all,

    I just recently purchased a MSX 150 and have found it has a problem starting back up when it is warm. When cold it starts instantly and idles perfectly. If I shut the machine off and immediately try to start it within a minute or two it fires right up. Trouble begins when I drive it for awhile and then shut it off and leave it sit for 30 minutes to an hour before trying to start it. Seems the engine must be slightly warm at this point (possible temp sensor?). When I try and start the machine it just turns over and over and will not start (I can hear the fuel pump hum). I have tried no throttle and giving it various throttle positions with no effect on starting. I can only get it to start when I hold the starter down for 30 seconds (I know this is a good way to burn up the starter but its the only way it will start). After 20-25 seconds of turning over I start to here it acting like it is going to start. If you immediately let off the starter it wont start. If you give it about 10 seconds of using the starter and the machine half fast running it starts and you can tell it was flooded out. The machine will then idle fine once it is running.

    Any ideas as to what to do. Not sure what options I have as it is EFI. Wondering if a reflash from Precision Sports in Canada would fix the issue? Not sure if that reflash has a better fuel map for the starting sequence? Plugs look good. Compression seems good. Looking to find a solution fast so I don't destroy the starter.

    Also, it just started going into limp mode at 35mph or 5400rpm's. Waste gate is not stuck and moving freely. Will run all day long up to 5300 rpm's or 34mph. Any thoughts. Dealers in MN just shake their head and do not really want to help. One says they will look at it but are not going to make any promises and are warning me it is going to be expensive.

    Thanks in advance for any advice,

  2. #2

    Join Date
    Jun 2010
    Lake front of michigan indiana
    i have same problem i did notice once that when it was towed it fire up like nothing happened and also when on trailer it has no issues must be something in the water l.o.l any way i found oil in my intake and both sensors slightly coated with oil but i can't test it anymore as i sent turbo for a rebuild i also noticed the engine bay excessively hot but no over heat or check engine lights hope one of the experts chime in cause when this thing runs it runs great other than the hicups that show up every now and then

  3. #3
    Thanks for the reply blu,

    Sorry to hear you have a similar issue.

    I did find a guy who says he has extensive knowledge with the weber engine. He mentioned that the fuel injectors may be leaking fuel into the cylinder when the machine sits for 30-45 minutes which would cause it to flood. I am going to bring it in so he can take a look at it and preform a leak down test. He has the digital wrench program and a test tank so hopefully he should be able to figure out why it keeps going into limp mode at 5,400 rpm's. I will post the results when he hopefully figures out what is wrong.

    If anyone else has any advice or ideas I would love to hear it.


  4. #4

    Join Date
    Jun 2010
    Lake front of michigan indiana
    hope he gets you running right. keep me updated as my turbo will be back in two weeks and i can do further testing the first time it happen to me i could have sworn i smelled raw gas whats also funny is that we rocked it side to side and it fired up and died almost like if exhaust got full of water

  5. #5
    Update: Ski is finally running great. The limp mode at 5400 rpm was caused by one bad MAP sensor. It also had a broken wire to the exhaust gas sensor which was replaced (heard that this is not essential but it was noticed on digital wrench and was an easy fix).

    Flooding when starting warm issue: Had an issue with the fuel pressure regulator in which it was over pressurizing the system when warm causing it to flood. It now starts and runs perfect even when warm. The guy who worked on the MSX said the key with the Weber engine is proper maintenance (frequent oil changes, etc). I think I will get the reflash done at the end of summer as I don't want a rich fuel map to cause cylinder wall failure down the road. Mechanic said he has personally never seen that horror story here in the midwest. Hopefully its good to go for the rest of the summer.

  6. #6

    Join Date
    Jun 2010
    Lake front of michigan indiana
    cool i guess i will be ordering a pressure regulator soon and in sept sending ecu off for a reprogram. are you the other guy i see once in awhile over in lake michigan with a blue & silver msx150 mines is all silver

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