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  1. #1
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    Exclamation 2001 135hp optmax

    I'm having a rough idle and slight miss in neutral and just off of neutral into trolling speeds on my 01 135hp opti 205hrs on engine. Changed fuel lines, fuel filter, tracker valve, new plugs gapped to .033-.034 new plug wires, fresh fuel with quickleen and quickare, new fuel bulb, rebuild low pressure diaphragm fuel pump. bought the boat used just noticed opti's require 1000mca batteries, looked at current battery and only offers 565 cold cranking amps could that be the cause of my miss and rough idle down low?

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    #2
    Also cleaned compressor strainer. With only 205 hours what could it be?

  3. Member
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    #3
    got enough batt voltage ???? low volts will beep at ya, may need good inj cleaning, hows it run wot ???? got correct plugs in it?????
    .................................................. ...the scariest thing in life is the unknown ...................................

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    #4
    runs great at wide open throttle, put plugs in that were recommended IZFR5G (NGK)@ .032-.033, had a loose plug at first oil seeping out, re-tightened all plugs to 20ft lbs no more issues. I do have a small battery, Currently running napa 8261 puts out 565 MCA. I have not had any beeps from the system while its operating. tested current battery for volts sits at 12.6 volts

    I just ordered a brand new Optima Blue Top D31M battery waiting for it to arrive on Saturday. Could the small battery cause idling issues and running rough at low speeds?



  5. Member
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    #5
    Quote Originally Posted by Muskyhunter08 View Post
    Could the small battery cause idling issues and running rough at low speeds?
    Yes. Optimax requires 800CCA minimum for engine alone no accessories. I have read numerous posts here with similar issues that were resolved when a battery of correct capacity was installed.
    _______

    Phil
    '09 Hewescraft ProV
    '09 150 Optimax


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    #6
    Serial number OT343374 2001 135hp optimax. 210 hours on engine. I've done all the maintenance and upgrades according to the 2.5L specifications page here. New fuel lines and bulb, new NGK IZFR5G plugs w/ gap and torque specs and new wires, new fuel pump rebuild kit, new spin on fuel filter on VST, cleaned compressor strainer, removed all main electrical terminals on alternator, starting solenoid, other main wires on engine cleaned added dielectric grease and re-torqued tight, Checked grounds on engine all good, replaced tracker valve with new one it's purple, pumped out all old fuel and replaced with 87 octane less then 10% ethanol from busy gas station, Added 1oz to every 5 gallons of gas quickleen and quickare to fuel and primed bulb into bucket makes sure I had fresh fuel in the lines. Added fresh Optimax DFi oil to remote tank, Changed lower unit gear lube. I have a new properly sized battery ordered and on it's way. The next step will be install new Optima Group 31 blue top once it arrives and hope that helps with the slight miss at low speeds 2-7 mph and rough idle. I'm at a loss if this battery doesn't fix it.


    What else should I be checking? any input would be great

    Thank you

  7. Member
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    #7
    Go back to square one. Check the basics.
    An engine needs 4 things.
    The correct fuel/air mixture,
    compression,
    spark
    in the right time.

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    #8
    Report back after installing the properly rated battery.
    _______

    Phil
    '09 Hewescraft ProV
    '09 150 Optimax


  9. Member
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    #9
    Installed new battery. Runs the same just turns over better. Check fuel and air psi fuel at 90 and air at 80 at idle. Engine seems to surge sometimes and increase rpm randomly with the slightest touch of the throttle. Runs erratic like a miss and dies. And when in neutral occasionally it will Rev up ever so slightly.

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    #10
    Not sure what it could be anymore pointers would be great. Had a local merc tech tell me that I should use power tune in the spark plug holes and let it sit over night then take it out and run it. Not to comfortable putting liquid in my cylinder heads.

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    #11
    Might be time for some hands on, eyes on expertise in diagnosing the problem.
    _______

    Phil
    '09 Hewescraft ProV
    '09 150 Optimax


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    #12
    Pumped twice cleaned fuel cell. Didn't help. Kinda of a where'd miss. I can kill the engine and restart and it won't miss again until 3mins to an hour

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    #13
    Then miss starts up again. Kill engine restart miss comes back but not right away

  14. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #14
    Cleaned out some responses that don't pertain to this engine at all.

    TPS is where I'd be looking....


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    #15
    Okay I will let my merc tech know a possible tps. and to test it. any special test to do on the tps? Also anything on how to adjust throttle ?