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  1. Member
    Join Date
    Jan 2016
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    Birmingham AL
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    42
    #61
    The latest chapter:
    Since my last post, the motor has been running great. The no start condition in my last post was caused by the injector harness not being plugged in all the way. Once I re-mated the connector - the motor fired right up.
    I have been using the boat and still have a reoccurring issue that is reminiscent of the issue that started this thread in the first place.
    The motor runs excellent, it starts, idles, and throttles up like a champ. I can run around at any RPM above 2000 all day without a hiccup. Has lots of power and runs like the clock. The issues start when I either idle for extended periods of time, or shut the motor off when hot. If I idle or troll for 5+ minutes, eventually the motor dies. I usually hear a change in sound and the motor dies over a period of about 10 seconds. Most of the time, the motor will re-start. To restart, I usually have to advance the throttle all the way. Once the motor re-starts, it does not want to idle and I have to rev it several times to keep it running in neutral. If I can then get it in gear without stalling and throttle up - it will run perfect until the next time I decide to stop and idle down. It will usually idle perfect for some time after a hard run, and then start acting up.
    If after the motor dies, I do not restart it immediately and instead let it sit for some time (20 minutes for example)- the motor becomes very difficult to start. It turns over and over and does not catch. I have verified that while this is happening, there is spark and fuel pressure. Eventually the motor restarts (this can take another 20 minutes of trying to restart it every several minutes) and after revving the motor in neutral, I can get it in gear and going. Once throttle is applied, it gets the boat on plane and runs perfect.
    This same scenario happens even if the motor does not die by itself, but rather I shut it off after reaching my fishing spot or the dock. It sits for 10 minutes, and then does not want to start.

    I feel that for some reason, the motor is flooding. Perhaps the VST is overflowing into the intake? The last time I had the VST apart, I replaced the float and needle. Is there a way to screw that up?
    The only other thing that comes to mind is over oiling. The motor seems to smoke quite a bit on restart after dying. Is there a way to check that? What can cause an intermittent over oiling condition?

    Any thoughts or troubleshooting suggestions?

    Mike

  2. Member
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    Jan 2016
    Location
    Birmingham AL
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    42
    #62
    Gents, any suggestions? I feel like I have gone through almost every system in this motor, and there is something small that keeps it from working 100%. My local Merc dealer does not seem to be an expert in these older EFIs and has not been able to find the problem. I really feel like this board is the best technical resource for troubleshooting so please help me out.

  3. Member
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    Jan 2016
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    Birmingham AL
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    42
    #63
    After an extensive online search, I have identified 3 possible causes for over-fueling or over-oiling being reported. I see that a malfunction of the VST float/needle valve can cause excess fuel to be dumped into the intake via the vent like. I see that common causes are a float full of fuel or debris in the needle seat. I also saw several mentions of instances where float and needle replacement did not fix the overflow condition - and the float tab had to be bent to adjust needle actuation. I will open the VST again and check all the components, but what are your thoughts on bending the tab?
    I also see that a damaged pulse fuel pump diaphragm can cause fuel leakage into the intake. I will again check and rebuild the pump.
    Lastly, a faulty check valve on the engine block or the oil inlet on the VST can cause improper operation of the oil system and potentially excessive oil being introduced - especially after engine shutdown if oil system pressure does not bleed off as designed. I have already replaced both check valves, but I will check them and test for oil system pressure after shut down.

    Any other suggestions?

  4. Member
    Join Date
    Jun 2013
    Location
    LONGVIEW TEXAS
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    13,941
    #64
    normally float adjustment is not needed unless someone has messed with it , look closly at the seat in inlet make sure its not scared and very clean, would only use oem diaphragm kit on your pulse pump , yes all the things you mentioned can be a problem with overoiling and flooding
    .................................................. ...the scariest thing in life is the unknown ...................................

  5. Member lpugh's Avatar
    Join Date
    May 2009
    Location
    Sacramento Ca
    Posts
    5,168
    #65
    Quote Originally Posted by SouthernNarwhal View Post
    The latest chapter:
    Since my last post, the motor has been running great. The no start condition in my last post was caused by the injector harness not being plugged in all the way. Once I re-mated the connector - the motor fired right up.
    I have been using the boat and still have a reoccurring issue that is reminiscent of the issue that started this thread in the first place.
    The motor runs excellent, it starts, idles, and throttles up like a champ. I can run around at any RPM above 2000 all day without a hiccup. Has lots of power and runs like the clock. The issues start when I either idle for extended periods of time, or shut the motor off when hot. If I idle or troll for 5+ minutes, eventually the motor dies. I usually hear a change in sound and the motor dies over a period of about 10 seconds. Most of the time, the motor will re-start. To restart, I usually have to advance the throttle all the way. Once the motor re-starts, it does not want to idle and I have to rev it several times to keep it running in neutral. If I can then get it in gear without stalling and throttle up - it will run perfect until the next time I decide to stop and idle down. It will usually idle perfect for some time after a hard run, and then start acting up.
    If after the motor dies, I do not restart it immediately and instead let it sit for some time (20 minutes for example)- the motor becomes very difficult to start. It turns over and over and does not catch. I have verified that while this is happening, there is spark and fuel pressure. Eventually the motor restarts (this can take another 20 minutes of trying to restart it every several minutes) and after revving the motor in neutral, I can get it in gear and going. Once throttle is applied, it gets the boat on plane and runs perfect.
    This same scenario happens even if the motor does not die by itself, but rather I shut it off after reaching my fishing spot or the dock. It sits for 10 minutes, and then does not want to start.

    I feel that for some reason, the motor is flooding. Perhaps the VST is overflowing into the intake? The last time I had the VST apart, I replaced the float and needle. Is there a way to screw that up?
    The only other thing that comes to mind is over oiling. The motor seems to smoke quite a bit on restart after dying. Is there a way to check that? What can cause an intermittent over oiling condition?

    Any thoughts or troubleshooting suggestions?

    Mike
    I would recheck your work in that area first and be sure it is properly adjusted. also possible it has picked up a contaminant causing it to leak when closed
    Thank You Leon Pugh

  6. Member
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    Jan 2016
    Location
    Birmingham AL
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    42
    #66
    Pulled the VST and pulse pump. The good: Pulse pump does not appear to leak, and the VST was perfectly clean inside. The bad - the float was partially filled with gas! Clearly, this motor hates me.
    I ordered a new float and pulse pump diaphragm kit. Will report once everything is back together.

  7. Member
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    #67
    haaaaahhhhaaaaa you aughta have about 300 a year that hate ya , like me , they love me when they feel better though
    Last edited by JOE54; 08-19-2020 at 03:21 PM.
    .................................................. ...the scariest thing in life is the unknown ...................................

  8. Member lpugh's Avatar
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    May 2009
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    Sacramento Ca
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    #68
    I do admire your perseverance
    Thank You Leon Pugh

  9. Member
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    Jan 2016
    Location
    Birmingham AL
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    42
    #69
    Replaced the VST float (did not bend the tab), re-built the pulse pump, re-checked the small filter in the fuel return by the regulator (perfectly clean); put everything back together and started the motor on the hose. Starts and idles as well as any 2-stroke I have ever seen. Checked for proper operation of the oil system - motor oil tank refills with the cap off. No residual pressure after 5 minutes of sitting with the engine off. Everything appears to work as it should.
    Let the motor idle and get up to temp. Shut off and restarted with different time intervals. Could not replicate the stalling/no-start problem on the hose. Because it was pouring down rain, I did not get a chance to drop it in the water and run it. Will report back next weekend. For now, I am cautiously optimistic.

  10. Member
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    Jan 2016
    Location
    Birmingham AL
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    42
    #70
    This motor hates me! Runs great when it wants too, but starts dropping ignition on multiple cylinders when it gets hot. Guess what, pulled the flywheel and found this:DefectiveStator_small.jpg
    The stator (a CDI unit I put in a long time ago) has a potted wire that sticks out past the coil and has been rubbing and shorting on to the flywheel. Hopefully, this is the gremlin I have been chasing all this time. Will update once CDI sends me a replacement (they promised to replace this under warranty).

  11. Member
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    Mar 2012
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    Pelham, GA
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    #71
    Nice find, hope it works.
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

  12. Member
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    Jan 2016
    Location
    Birmingham AL
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    42
    #72
    I feel like I can finally say that its fixed! I replaced the stator (CDI sent me a new one free) and have run the boat several times - with no issues. The motor runs perfect!

  13. Member
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    Pelham, GA
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    #73
    Nice, bet that feels good.
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

  14. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    Greenville, SC (US)
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    #74


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  15. Member
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    #75
    "endeavor to persever" LONE WATIE outlaw JOSEY WALES
    .................................................. ...the scariest thing in life is the unknown ...................................

  16. Member lpugh's Avatar
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    #76

    You have my admiration for winning a long fought battle
    Thank You Leon Pugh

  17. Member
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    Aug 2020
    Location
    St Johns FL
    Posts
    1
    #77

    Same Problem 200 Merc Lases Power

    Quote Originally Posted by SouthernNarwhal View Post
    I feel like I can finally say that its fixed! I replaced the stator (CDI sent me a new one free) and have run the boat several times - with no issues. The motor runs perfect!
    I read this whole thread through as I am having almost the same issue with a 24' Glastron I just bought last week with a totally(allegedly) rebuilt (New power head)200 MERC 2004. 4 Runs out into the St Johns River 3 of 4 trips lost power just exactly like you did and it after it warmed up. On the restart it cant get past 2000 rpms- I can only guess RPMS as the Tach doesn't work. Dealer I bought it from doesn't want to take it back in too quickly here so $22,000 in I am already having to take on my own repairs on a boat I have used 4 hours, its not probably even totally broken in yet. I looked over the block and it looks like most of the parts outside the block are brand new except for the CDM's. I called a Mercury guy here in Jax an old pro and he actually advised me that its most likely the stator. Looks like its about $400 though so before I spend it to replace it I think I'm gonna get a third opinion on this.

  18. Member
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    #78
    very possible stator on it also ,start you a thread with your ser number so we can see what fixed it
    .................................................. ...the scariest thing in life is the unknown ...................................

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