Results 1 to 16 of 16
  1. #1
    Member
    Join Date
    Feb 2021
    Location
    Flagstaff, AZ
    Posts
    7

    2009 Optimax 200 Pro XS Sluggish, Low Power, Good Idle

    2010 Bass Cat Pantera IV
    2009 200 Optimax Pro XS
    S/N: 1B766129
    Prop: 25p Fury
    Current Max RPM: 4200-5500
    Idle W.P.: 2-3psi; WOT W.P.: ~20psi
    Smartcraft gauges
    Cranking Battery: Duracell (East Penn) 31DCX Flooded Lead Acid, MCA: 860, CCA: 700, RC: 205Minutes
    Checked compression at operating temp, all plugs removed, battery (above) freshly charged: 80-88psi.

    Hi All,

    Hoping for some advice here. Just had the motor in the shop to address a hard starting, rough idle, low power situation, after which it was determined the fuel pressure regulator diaphragm was cracked and was replaced (along with spark plugs and new batteries, cranking and 2 trolling are the model above). Next trip out, motor starts, idles, runs great; back in business. Second trip out about two weeks later, motor starts and idles fine, but is down on power and can barely get boat to plane and maxes out at about 4200rpm. However, this only happens about half the time. Can sometimes shut it down and restart and everything is fine for a run across the lake. Sometimes it will surge/sputter (normal power/low power/normal power, etc.) while trying to get on plane. After doing some reading, I feel like my cranking battery might be too small, but I am hesitant that it's the cause of my performance issue. The shop I used is booked out a couple months so I started doing my own troubleshooting. I checked spark in the driveway with muffs on with a timing light and have spark at all cylinders. Checked plugs and one looked to have alot more carbon deposits that the other 5, so I suspected a bad coil (after some reading that coils can fail intermittently under power, and I can only check spark at idle). I then replaced that one coil (with a rev C coil, all others are rev B). No change in performance and noticed the new coil runs HOT, too hot to touch. Tried swapping to a different cylinder and no change in performance, still runs hot. I now suspect I have purchased a bad (new) coil. I'm tempted to spend the roughly $1000 to replace all 6 coils, but am hesitant to spend that kind of money just to 'see what happens'. Any other low hanging fruit I can try first, or advice on how to proceed? Thanks in advance!

  2. Member
    Join Date
    Jun 2004
    Location
    Bentonia, MS 39040
    Posts
    3,354
    #2
    Usually u can pull plug wire and find. If coil is noticeably hotter than others I would replace the one that is running hot, u have a problem there for sure
    Ron Fears
    Stroker/300XS
    1E003823

  3. Member
    Join Date
    Jun 2004
    Location
    Bentonia, MS 39040
    Posts
    3,354
    #3
    Coil is under warranty if new
    Ron Fears
    Stroker/300XS
    1E003823

  4. Member
    Join Date
    Jun 2013
    Location
    LONGVIEW TEXAS
    Posts
    13,938
    #4
    ^^^^^^ +1 oem parts have one year warranty
    .................................................. ...the scariest thing in life is the unknown ...................................

  5. Member lpugh's Avatar
    Join Date
    May 2009
    Location
    Sacramento Ca
    Posts
    5,164
    #5
    Use a KV tester to test the coils, set the air gap to .625 5/8 inch, this will force the coils to max output. Be sure battery is charged and charging system is working, bet you find 1 or more that will work at a 1/4 gap but fails at greater loads.
    At light loads coil output may only require 5 to 10K volts, at heavy loads may need 40K. This is why you can miss a bad coil with a timing light, very good quick test for dead missfires though
    Thank You Leon Pugh

  6. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    94,941
    #6
    Make sure you have the CORRECT coil. There are two design coils- a single-strike and a multi-strike. Installing the wrong coil will cause problems- there is a slight difference in the overall length between them (about 3/8 - 1/2").

    Did you use a timing light to check for spark (good flashing pattern) on all six plug wires?


    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

  7. Member
    Join Date
    Feb 2021
    Location
    Flagstaff, AZ
    Posts
    7
    #7
    Thanks for the feedback guys. I am getting a new coil sent to me under warranty. As far as having the CORRECT coil, I did actually get the wrong coil the first time around, I got the version meant for the 250; had to return for the version meant for the 200/225s. So, I THINK I have the right PN (8M0077473) for my motor (checked on Mercury parts catalog using my motor SN). However, even with the correct coil, it still runs very hot. And to answer your question, Don, I did check for spark with a timing light on all six plug wires (have good, steady flashing). I also just purchased an adjustable spark tester to test the coils at large air gaps (heavy loads). I will do that here in the next couple of days; fingers crossed I can find a bad coil.

  8. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    94,941
    #8
    8M0077473 should be correct (longer, single-strike ignition coil).


    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

  9. Member
    Join Date
    Feb 2021
    Location
    Flagstaff, AZ
    Posts
    7
    #9
    Ok, just checked all six coils with a spark tester in the driveway: #1-4 and #6 cylinders all had good, consistent spark out to a 7/8 - 1" gap. The #5 coil was the only one that had an intermittent spark at 7/8" air gap. I live at 7,000ft, so after some reading, the breakdown voltage in air drops with altitude (lower air pressure), so it makes sense why I can run a bigger air gap. Anyway, I was hoping for something much more different or a bigger change (like intermittent spark at only 1/4" gap), but I plan to replace this #5 coil with the new warranty replacement coil and run it on the lake this weekend. Any other thoughts?

  10. Member
    Join Date
    Apr 2015
    Location
    ponchatoula la
    Posts
    1,490
    #10
    Was #5 cylinder the plug with more carbon buildup

  11. Member
    Join Date
    Feb 2021
    Location
    Flagstaff, AZ
    Posts
    7
    #11
    No, it was #2 cylinder with the extra carbon buildup on the plug.

  12. Member
    Join Date
    Jun 2008
    Location
    Whitehall Wisconsin
    Posts
    491
    #12
    Have had it happen more then once brand new NGK`s that were bad, idle fine under load start to miss, cutting in and out.

  13. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    94,941
    #13
    And quite often when there's a problem on one cylinder it affects other cylinders more than the one malfunctioning.


    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

  14. Member
    Join Date
    Feb 2021
    Location
    Flagstaff, AZ
    Posts
    7
    #14
    Quick update: got the new replacement coil but decided before I installed it to test #5 coil to make sure I could duplicate the intermittent spark at 7/8" gap. Not the case, it had good repeatable spark out to 1" gap. So it seems all coils are just fine. I then took the advice from TomP. and replaced the spark plugs. Then ran it on the lake for several hours, starting and stopping, taking breaks to fish, etc., and all is well, no loss of power. Never occurred to me that brand new spark plugs could be defective. Learned something new! Thanks all!

  15. Member
    Join Date
    Jun 2013
    Location
    LONGVIEW TEXAS
    Posts
    13,938
    #15
    good info thanks
    .................................................. ...the scariest thing in life is the unknown ...................................

  16. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    94,941
    #16
    Good catch! That's the old "New does NOT necessarily mean "Good"" quandary.


    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