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  1. #1
    Member HASLAG's Avatar
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    97 mercury 175 efi issue

    Ok so ran it all day ran fine went to start it cranked like no compression.got it started and ran ok until I came to a idle now will not start. It cranks like no compression.
    Mercury
    Serial # for mercury og508260
    2005 champion 196 oh what a ride

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    #2
    do a lil compression test and see , spark test to while your there
    .................................................. ...the scariest thing in life is the unknown ...................................

  3. Member HASLAG's Avatar
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    #3
    Ok so the next morning I checked it and it started ran good on trailer for 10 minutes.
    so I decided to go fishing ran around local and shut off several times all seemed good ran about 6 miles up lake and fished and started to head back started and idled for 30 seconds died same thing.
    got it home I do have spark I can hear fuel pump run.
    I don’t have pressure gauge at house but if I push on shrader valve with pump running I have pressure but once it shuts off nothing!
    2005 champion 196 oh what a ride

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    #4
    Do you have the original fuel line with the in-line check valve? I have a 97 150 EFI and it used to quit on me. I was told I might be getting some sort of air/vapor lock
    in the fuel line. I removed the check valve and replaced the fuel line with the ethanol resistant type 10 yrs. ago. No problems since then.

  5. Member HASLAG's Avatar
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    #5
    Had all new fuel lines and bulb replaced last year
    2005 champion 196 oh what a ride

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    #6
    Quote Originally Posted by HASLAG View Post
    Had all new fuel lines and bulb replaced last year
    I'm talking about the check valve that is just outside of the fuel tank. You cant see it unless you expose the tank. As I recall it is a 90 degree fitting.

  7. Member HASLAG's Avatar
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    #7
    Ok guys i can not figure this out it has to have something to do with heat after it gets hot is when it acts up but some time will not start for 6 hours then sometime a hour after it acts up.
    I have fuel and fire when it does not start
    2005 champion 196 oh what a ride

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    #8
    how was fuel delivery checked ??????
    .................................................. ...the scariest thing in life is the unknown ...................................

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    #9
    Had this same issue with my 99 175 efi. Run great one day, next day wouldn’t start, then it would, then it would shut down, then it would run. Every time took it to the dealer it would run fine for them to do tests and find nothing. Finally did it one day while on the water and called the dealer. Went through some things and found the problem. Ended up it was the ecm and the drivers in it. Guess they come loose over time. Couldn’t find another one anywhere, there is now a 175 opti on my boat. I did notice it was definitely worse when it was warm out. The way we diagnosed it was with the cowling off you couldn’t here the fuel pump run. Dealer told me how to jumper it and pump turned on right away. As soon as I disconnected the jumper pump wouldn’t work again. Then I banged on the ecm and it started working again. Hopefully that isn’t your issue because those ecm’ are impossible to find.

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    #10
    I had to pull my fuel lines of and blow through each one until I found the one that collapsed inside,,,I changed them all after I found the problem,,, ethanol eats lines from the inside / out,,,,,,my line was so bad,I could hardly blow through them,,,

  11. Member Nikon Man's Avatar
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    #11
    I'd be a little concerned that your injectors may have some of that hose material in them, I'd recommend having them cleaned. It's a pain I realize but on the flip side I'd hate to see you lean out a cylinder and then you'd have even bigger issues.........just a thought.
    Gary



    Growing old is inevitable, growing up is optional.......

    S.W. Ohio

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    #12
    HASLAG, did you figure this out? I has a similar problem with my 1998 Merc 175 efi yesterday. Started fine and ran good, about about a 2 mile run to fish I shut it down and after about 10 minutes tried to start it and it would not start without the choke (shifter disengaged) throttle pushed forward but wouldn't idle otherwise. Finally was able to shift into gear fast enough and it ran good until I went to put it on the trailer. Frustrating.

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    #13
    if you have spark on all 6 i would be concerned about ECU
    .................................................. ...the scariest thing in life is the unknown ...................................

  14. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #14
    Quote Originally Posted by Takeum View Post
    I had to pull my fuel lines of and blow through each one until I found the one that collapsed inside,,,I changed them all after I found the problem,,, ethanol eats lines from the inside / out,,,,,,my line was so bad,I could hardly blow through them,,,
    Probably older line, line installed improperly, or subjected to higher ethanol content than rated for. But yes, that happens.

    HASLAG: When this occurs and the engine won't start, LISTEN for the fuel pump at key "one". No pump, no start.

    Make sure ECU wiring is properly connected, lockring intact, and connection secured in the bracket properly.

    Make sure there is a ground strap for the ECU (from intake cover screw).

    Possible ECU driver loose on the board (meaning the ECU no longer provides a modulated GROUND for the fuel pump).


    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).
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    #15
    Quote Originally Posted by DaleMc0622 View Post
    HASLAG, did you figure this out? I has a similar problem with my 1998 Merc 175 efi yesterday. Started fine and ran good, about about a 2 mile run to fish I shut it down and after about 10 minutes tried to start it and it would not start without the choke (shifter disengaged) throttle pushed forward but wouldn't idle otherwise. Finally was able to shift into gear fast enough and it ran good until I went to put it on the trailer. Frustrating.
    Really should start a new topic for your engine including engine serial number - Please READ BEFORE Posting

    Are you pumping the bulb prior to EVERY engine start?
    _______

    Phil
    '09 Hewescraft ProV
    '09 150 Optimax


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    #16
    My apologizes, problems sounded familiar so was inquiring whether he got it figured out.

  17. Member HASLAG's Avatar
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    #17
    So the best I can tell I think I am loosing fire on some cylinders I can not get it to quit at this time for more than about 20 minutes and by the time I get hood off and try several cylinders some have fire and some don’t then it starts
    2005 champion 196 oh what a ride

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    #18
    which ones 1,3,5 or 2,4,6 remember if your loosing 1 3 5 then injectors will not operate on 2 4 6 either
    .................................................. ...the scariest thing in life is the unknown ...................................

  19. Member HASLAG's Avatar
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    #19
    The star board d side is loosing spark
    2005 champion 196 oh what a ride

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    #20
    most likely switch box inside one /1,3,5
    .................................................. ...the scariest thing in life is the unknown ...................................

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