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  1. #1
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    1999 200 Optimax Issues

    All... I recently bought a "fixer upper" Ranger 518 VX bass boat with a 1999 200 Optimax on it. The motor would not start, or run initially so I bought a maintenance manual, and went to work :). After replacing the low/high pressure fuel pumps, rebuilding the diaphragm fuel pump, replacing a coil, the spark plugs, and a few fuel lines, I have it running pretty well. However, there are three specific issues I'm struggling to resolve.

    The first issue is that at WOT I can only turn a standard 25P prop about 5400 rpms, but the boat does run 69 mph (GPS) while at that range. It's just that everyone is telling me this boat/motor combo should be turning the prop at the upper end of the rpms, which is 5750, and I don't want to leave anything on the table :).

    The second issue is that the motor surges some when switching between neutral, forward, and reverse. An example is when I get up around a dock trying to park it. When shifting quickly between the gears, the motor rpm's will run up/down for just a couple of seconds before settling down (like it is doesn't know where to stabilize???).

    The third issue is that when I take off, I get a hesitation, but not like a stumble or it's stuttering. It's just like I pressed the hot foot down, and the motor doesn't react for a second, or so??? Once it revs though, it puts the boat on plane very well, and runs nicely after that.

    Other than these things, I'm very happy with this motor. Can anyone shed any light on some things that could cause these symptoms? Thank you.

    1. Engine Serial Number 0G886121
    2. Year/Make/Model 1999 / Merc / 200 Opti
    3. Prop you are Running 25P Tempest
    4. Current Maximum RPM 5400 RPM
    5. Idle and WOT Water Pressure Readings 650 rpm @ idle / 23 PSI WOT water pressure
    6. Smart-craft or Analog Instruments? Analog

  2. Member
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    #2
    First issue: Your tachometer is likely not reading correctly. Have the RPM's verified.

    Second issue: Idle speeds are computer controlled. Shifting quickly back and forth would indeed cause the condition you describe.

    Third issue: Try adjusting the PVS plugs in the prop.



  3. Member
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    #3
    Thanks for the suggestions. I have thought about questioning the tach since I know the speed is correct on my GPS. I wasn't sure I could be getting 69 mph at 5400 rpm??? The only thing about my issue with the surging, is it's really happening when I get the throttle control right before the neutral position (whether going from forward to neutral or reverse to neutral). It's not so much shifting quickly, but whenever shifting in/out of gear, it's like the motor wants to idle up/down searching for where it needs to be??? Maybe everything is ok??? It starts easily, idles well, and seems to run fine???

  4. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #4
    Shift Position Switch is causing the engine to stumble when shifting out of gear. This is by DESIGN.

    ECU utilizes that switch to know when to add timing to stabilize for shifting, or stutter the engine to ease shifting to neutral.

    As Savage suggested, verify tach and try some more PVS ventilation.


    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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  5. Member
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    #5
    Thank you. The tach is original so I'll just start with ordering a new one. Appreciate the responses, and ideas - Thanks again.

  6. Member
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    #6
    Verify your RPM's with a "Tiny Tach".



  7. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #7
    Quote Originally Posted by Savage View Post
    Verify your RPM's with a "Tiny Tach".
    +1... or some other "inductive pickup tachometer" (some mid to high end timing lights contain this feature).


    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