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  1. #1
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    75 Optimax no start

    07 Optimax 75HP-approx 100 hrs.
    Kill switch on 1beep cranks no start.
    kill switch off no beep cranks no start.
    cables , connections in great shape.
    spins over rapidly, doesn’t start.
    Fired up as usual at ramp, ran great as usual same morning.
    Died in gear barely moving, hasn’t hit a lick since.
    check battery cranking for 11.2V ?
    check for spark?
    What are some things to check?
    TYIA!!

  2. Member
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    #2
    any spark at plgs ???????
    .................................................. ...the scariest thing in life is the unknown ...................................

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    #3
    Didn’t appear to but we were only holding plug wire in hand at campground.
    I will do much more thorough job as we are back home now.

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    #4
    Level 1 Mercmonitor also, system ok,and never heard any alarm.
    Dons fuel cocktail and non ethanol always.

  5. Member
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    #5
    youd prob known it by hand shock possible crank position sensor failed
    .................................................. ...the scariest thing in life is the unknown ...................................

  6. Member
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    #6
    Thanks joe54, I ordered me a CPS from Don.
    Ill have it on hand if needed.
    Havent done the Basic trouble shoot yet.
    Ill update soon.
    Flat camper tire, Optimax won’t start, also ruined a spindle.
    costly aggravating camping trip for sure.

  7. Member
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    #7
    i feel it
    .................................................. ...the scariest thing in life is the unknown ...................................

  8. Member
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    #8
    My 2012 75 hp Optimax had no beep alarm (chirp) when starting, it started and ran fine, but was told by dealer that the ECM did not give any audible alarms for any faults, ECM had to be replaced under warranty ($1300.00 Can.). Can you have the computer scanned ?

  9. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #9
    Need to focus on basics rather than PCM at this point. Compression, Spark and fuel.


    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

  10. Member
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    #10
    Installed CPS I received from Don, which got to Tn fast.
    Did not fix the no start!!
    Ill have to make time for the Basics as stated.
    Have the manual, so gonna have to make time to follow along.
    Definitely hear that big pump, I’d bet against battery.
    Thanks for all the replies, I’ll update later.

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    #11
    Got spark from coils to plugs.
    Low pressure fuel pump reading 20psi.
    Hi pressure pump reading 30 psi.
    currently no means to check air psi.
    No start!!
    Last edited by Jenksracin; 08-20-2022 at 06:11 PM. Reason: Error

  12. Member
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    #12
    gotta have right air psi to start as air psi rises fuel psi should follow
    .................................................. ...the scariest thing in life is the unknown ...................................

  13. Member
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    #13
    Gotcha!
    Rechecked low pressure fuel today- zero.
    Geez.

  14. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #14
    Make sure you're connected to the fitting at the back of the VST, with no leaks.

    Pump primer bulb FIRM.

    Cycle key ON and water pressure. It WILL drop when the pump stops (but should hold at 15 or so PSI).


    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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    #15
    Found sleeve (seal) at exit of hi pressure pump torn!!
    Both pumps fire off at a bump of DC jumper wires.

  16. Member
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    #16
    bet it starts now with correct fuel psi
    .................................................. ...the scariest thing in life is the unknown ...................................

  17. Member
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    #17
    I feel your frustration! I have found the more big boy toys you have, the more problems for sure. I recently sold my camper and pontoon boat for those reasons plus getting older doesn’t help!
    Quote Originally Posted by Jenksracin View Post
    Thanks joe54, I ordered me a CPS from Don.
    Ill have it on hand if needed.
    Havent done the Basic trouble shoot yet.
    Ill update soon.
    Flat camper tire, Optimax won’t start, also ruined a spindle.
    costly aggravating camping trip for sure.

  18. Member
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    #18
    Sleeve/Seal install wasn’t to big an ordeal.
    Don’s tip on lubing sleeve,awesome.
    Thanks to all.
    Joe&Don she’s running!

  19. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #19


    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