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    1978 Mercury Black Max V1500, Surging at high throttle.

    On this one, I did try the timing light on all 6 cylinders to make sure they were all 6 firing and they were. Forgot to state that above.
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    1978 Mercury Black Max V1500, Surging at high throttle.

    I love finding gems like this one when reading tech manuals, This just makes you feel like you are standing there talking to an old guy who absolutely knows what he's talking about! LOL
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    1978 Mercury Black Max V1500, Surging at high throttle.

    Well I used a different manual than that one but will try it that way and see if that helps. Also replacing the champion spark plugs with NGK after work today to see if that makes any difference. Going with NGK Standard Spark Plug (BU8H) Part # 6431 which seems to be the recommended ones. Worth...
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    1978 Mercury Black Max V1500, Surging at high throttle.

    Engine off, boat in gear can turn engine over with the prop going CC. In neutral prop spins freely. On hose engine seems to reach full speed on prop, in water it doesn't get to 2k RPM. Previously when it was surging it would push the boat at about 12-20MPH so I have no question about it being...
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    1978 Mercury Black Max V1500, Surging at high throttle.

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    1978 Mercury Black Max V1500, Surging at high throttle.

    However in gear it doesn't have the power to push itself up on the traylor and in open water runs about 6 mph on the gps. I have verified that the timing is correct and all carbs are working and in sync. I removed the electronic fuel pump and reinstalled the rebuilt mechanical fuel pump with all...
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    1978 Mercury Black Max V1500, Surging at high throttle.

    Replaced the switch boxes now on the hose or in the water in neutral it sounds like one would think it should.
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    1978 Mercury Black Max V1500, Surging at high throttle.

    Hmm that makes sense I guess, so the Neon one basically sux then? The adjustable one can help me determine the actual power of the spark generator by the distance it can jump, from my research. Sound right? On order now.
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    1978 Mercury Black Max V1500, Surging at high throttle.

    Here s the Slow Motion recording at about 2k rpm
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    1978 Mercury Black Max V1500, Surging at high throttle.

    For reference: https://www.cdielectronics.com/wp-admin/admin-ajax.php?action=cdi_spget&spurl=https://sharepoint.cdielectronics.com/Controlled%20Documents/Installation%20Sheets/IS-114-7778.pdf Also, as to the gaskets, Yes I have used this material many times in many different applications with...
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    1978 Mercury Black Max V1500, Surging at high throttle.

    Ok Link and sync done, wires, plugs and coils replaced. Now to get a moment to drop it in the lake and test it out. Any recommendation of where to get a good set of switchboxes for it? The ones i have on it are new but from amazon and if this doesn't fix it I am thinking of replacing those...
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    1978 Mercury Black Max V1500, Surging at high throttle.

    Wires on order now, will try a few other places for the link and synch. Will get back to you guys once that is done because it certainly sounds like a reasonable plan. I greatly appreciate the advice!
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    1978 Mercury Black Max V1500, Surging at high throttle.

    Interesting, didn't know there was a difference, see now I learned something new and am off to find some solid core wires. Also after doing some testing last night I found that if I unplug the top 2 or the middle 2 sets of plugs the engine really doesn't run that much different, you can tell...
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    1978 Mercury Black Max V1500, Surging at high throttle.

    I have looked all over for instructions on how to do that and have asked around at several boat shops and have been told that that engine all you can do is make sure the carbs close 100% at end of the throttle and 100% open at full throttle, I have them all lined up and at closed throttle they...
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    1978 Mercury Black Max V1500, Surging at high throttle.

    Sorry, yes entire fure system was replaced except tank which was carefully cleaned. I installed a new fuel water separator and filter and all new lines even new fuel tank filler neck. Pre mixed to 50:1 with good fuel and oil. All fuel lines on the engine were replaced as well.
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    1978 Mercury Black Max V1500, Surging at high throttle.

    Here is the other side of the engine
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    1978 Mercury Black Max V1500, Surging at high throttle.

    Greetings, So I have a Mercury 150hp Black Max that starts great and Idol's great, but any thing over about 1/4 throttle and it starts surging and will not go over 3100 rpm, even in neutral. So far I have replaced all electronics, Stater, trigger, switch boxes, all wires, Plugs, coils...
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    1978 Mercury Black Max 150 Tilt/Trim Pass Through ?

    Awesome, Thank you! So far it's been a great adventure in learning. I have wired everything from M1 Tanks an humves to houses and the like and, pow, boats are way different lol. Got a lot to learn which is exactly what drives me to keep going. Will post pictures and the like as soon as I have...
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    1978 Mercury Black Max 150 Tilt/Trim Pass Through ?

    Just starting a rebuild of a 1997 Javalen 389FS that has a 1978 mercury black max 150hp on it. When talking to a friend we were wondering if the lower motor mount bolts are actually where the Tilt/Trim tubes are supposed to come through or is this unsafe? Very new to this and just never seen one...
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