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  1. #1

    Angry mercruiser 4.2L 300hp help

    my engines normally are great, just started making a knocking sound and loss of power
    I tried all the usual things, had all the injector tips replaced anyway, not that, cos I have 2 engines' the same I swapped some parts to try identify the problem, so if I disconnect the fuel solenoid it stops knocking and sounds great, but I get white smoke, so I think iv advanced the timing but at least its not anything inside the engine, so ive changed all the sensors, still same, anyone got idea what it could be

  2. #2
    Join Date
    Apr 2016
    Location
    barnegat NJ
    Posts
    2,706

    Default Re: mercruiser 4.2L 300hp help

    test fuel pressure knock ,sensor might be bad
    Last edited by johnnygjr; 09-10-2016 at 03:06 PM.

  3. #3

    Default Re: mercruiser 4.2L 300hp help

    Quote Originally Posted by johnnygjr View Post
    test fuel pressure
    how would the fuel pressure make it knock and then ok when remove wiring from solenoid
    do you think its a injector pump problem, although when I bleed it its very strong pressure
    I know by unplugging the solenoid wires it changes the timing and maybe compensating for something else

  4. #4

    Default Re: mercruiser 4.2L 300hp help

    what sensor are you talking about, I had the solenoid tested and I tried a new one anyway cos I had one

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