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  1. #1
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    Merc 280 fouling spark plugs

    I just bought this Merc 280 EFI. I put in new spark plugs as recommended -- NGK BUZHW. One after the other fouled within 60 seconds of running. Am I using the right spark plugs for this motor, or do I have another problem (fuel injection)? Compression is great: 150 PSI on all cylinders. The motor year is 2000. The motor is all stock, never been opened, with the standard ECU.

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  2. #2
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    The correct spark plugs for a 280 are NGK BPZ-8H-N-10. What fuel/oil ratio are you running? Should be 40:1 If your running too much oil that will foul the plugs quick. Start by installing the correct spark plugs and make sure your fuel/oil ratio is correct. If it still fouls the plugs that quick then I would send the injectors to Brucato. NGK BUZHW plugs are for older 150's and smaller motors.

  3. #3
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    If you don't know the maintenance history on the engine, just send the injectors to Brucato and save yourself the trouble in the future. You wil be pleased, and use less fuel too. I can't say enough about their service.
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  4. #4
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    fouling plugs

    thanks. i am runing 40-1 klotz r50. did not find any mercury performance blend oil. my fuelpressure is 40 psi. is that ok or not. the fuelpump pressure is over 60 psi.

  5. #5
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    40 PSI is fine at the motor and should have a gold colored regulator. The pump will "dead head" way above that number ...

    I'd switch over to Penn. 100% syn. if it were my motor . It will burn WAY cleaner than the Klotz..

    40:1 ratio is fine running 8000 RPM's or lower.

    And the correct plug for that motor is indeed NGK BPZ-8H-N-10 gapped @ .035" I'd also follow earlier sound advice and send your injectors to Brucato you won't regret it!

    My .02 WELCOME to SCREAM and FLY !!!!!
    Jay
    Jay @ JSRE


  6. #6
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    I personally have never ran the klotz. I've heard both good and bad about it. I run pennzoil full synthetic in my 280. I find its cleaner burning. The stock gold fuel pressure regulator on 280s is set at 39lbs so you are in the right area pressure wise...fuel pressure wont foul the plugs though. Like i said put the correct plugs in it. That has alot to do with it. And being you just bought the motor theres no telling the condition of the injectors. My motor ran perfectly fine, or so I thought until I sent the injectors to Brucato for cleaning and flowing. Night and day difference in performance and fuel consumption.

  7. #7
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    Had the same problem with my 280 did the the injector clean
    made difference but still the plugs kept fouling I was told to try when just idling around trim the motor up so the exaust is clear of the water let it breath this worked for me

  8. #8
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    Hey guys, I'm a little late to the party but I am having the exact same issue with my 280. I've been told the correct spark plugs for this motor NGK BPZ-8H-N-10 have been replaced buy the NGK BPZ-7H-N-10... not sure how true this is or not.

    Where you ever able to get your issue resolved ModVP501? I'm pulling my injectors right now to send over to Brucato like the rest of this thread had recommended. I have about 39psi to the rail and running a 32:1 mix with the Mercury Racing Synthetic Blend oil. I know everyone who has commented on this is running 40:1 but I never experienced an issue like this with running the oil a little rich.

    I bought the boat a few months ago as they previous owner had just re-powered the boat. I brought the boat home initially and checked compression (150psi each cylinder), and hooked it up to the computer to see the hours, and other things of that nature for some peace of mind.

    Curious to see if simply sending off your injectors to Brucato solved the problem.

    Thanks!!

  9. #9
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    my 280 would drop plugs, it ended up being the exhaust cover gasket was leaking. no water on the plugs you could see, but after I found that no more plug problems.
    2008, 2012, 2013 and 2015 world series of ice drags champion prostock 800!!
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