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    4.3lx intake manifold question

    Not saying you're wrong, but are you sure the manifold is a single plane or if so is it original. Boats typically use a dual plane manifold and if your holeshot is good, that's probably what it has. Doubt you'll see any performance increase from a manifold and carb change unless you're going...
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    Mercruiser 4.3 LX Gen+, Hydrolock, no water in oil.

    Hydrolock may be due to engine shutting off unexpectedly. Was it at significantly higher rpm than idle when it happened?
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    5.7 GSIPEFS Timing??

    Get a timing light. Turn engine over by hand til #1 cylinder on TDC on compression stroke. Put distributor in with rotor pointed toward number 1 cylinder. Make sure distributor is fully seated and engaging oil pump shaft. Put distributor cap on and replace plug wires in proper order starting...
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    Volvo Penta 5.0 GL-C Rebuild Help

    Engine internals are no different from automotive but some say head gaskets have to be marine, some say only if used in salt. Don't use that copper spray stuff. Get fel-pro gaskets. Up to you if you are replacing core plugs, they are brass. Timing cover, if plastic, will need to be replaced...
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    1991 carburated 4.3 fuel pump output.

    Well sounds like you found your problem. Hopefully that takes care of it
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    Urgent help - boat fell off trailer while backing down ramp

    Agreed. I'd be checking thoroughly for a cracked transom. If there's sealer around the drive it has been leaking before, which most likely means rotted and weakened transom unless it's wood free.
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    Coil ground

    The bracket is for mounting not grounding.
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    Engine Replacement Compatibility

    If you replace the engine make sure it is a vortec. If you decide to upgrade to a 4 barrel, you will need a 4 barrel vortec intake to fit square or spread bore carb of your choice.
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    6.2 L Rebuild Noise

    When I watch the video, I was counting 4 or 5 knocks per second but now I hear another quieter knock after the louder one so yeah one knock per revolution essentially.
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    Correct RPM for setting timing on muffs

    With boat in water in neutral, disconnect throttle cable. Adjust idle to 650-700. Adjust mixture screws as directed. Then put in forward gear and adjust idle to 650-700 if it has dropped. Put back in neutral. Reconnect throttle cable, adjusting so that it doesn't change idle rpm in gear.
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    What is this port?

    Built in cooler drain?
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    Oil pressure on 1986 OMC cobra 5.7

    OIl pressure is a little low compared to a new engine but acceptable especially if the engine is original. 10 psi per 1000rpms for a small block is typically fine. Keep an eye on your oil. If it gets milky/cloudy you have water intrusion, likely due to a head gasket or exhaust gasket leak.
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    What is this port?

    If there is anything connected to that port on the inside, find it and trace where it goes. If it's connected to the bilge pump, that's a terrible location for the bilge exit. Blower only moves air through the engine compartment. Won't be remotely near the waterline.
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    6.2 L Rebuild Noise

    That does sound like a bottom end knock but it's frequency seems too low. Makes me think valve train but it doesn't sound like a lifter or rocker. The hollow sound is reminiscent of a crank throw hitting the oil pan or a con rod like Bt Doctur mentions but, again, frequency seems too low. Any...
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    Multimeter tach reads RPMs too high

    Disconnect the throttle cable from the carburetor and make sure that the throttle is closed or very near closed.
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    3.0 power loss

    Check your fuel tank vent and anti siphon valve.
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    Multimeter tach reads RPMs too high

    Distributor is driven by camshaft so it spins at half of engine rpm. No wasted spark. I have had success calibrating a tach with a digital strobe. You can download a free app on your phone for a strobe tachometer. Make a white mark on your crank pulley and set the strobe frequency to make the...
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    1976 Mercruiser 165 Engine Tick & Low Oil Pressure

    Agree with Scott06. Another option I have used with good results is the Motor Medic motor flush. Put it in and IDLE ONLY for 5 minutes then change oil. Use a heavier weight oil. The flush cleans a lot of junk out and the heavier weight oil will increase pressure on a worn engine.
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    1980 3.0L strange overheat issue

    Had a 1969 2.5 mercruiser back in the day. Got the boat for free and was broke so I just put a big stainless washer I scrounged up in place of the thermostat. The hole was big enough to allow flow but enough resistance to force water into the engine. Never got hot but also never got up to normal...
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    1980 3.0L strange overheat issue

    Overheating can occur when no thermostat is present. Water flows via pressure, resistance, and gravity. The engine block is lower than the water inlet and outlet so there's no natural flow through it. The circulating pump circulates the water through the engine but without a thermostat most of...
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