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    Fuel pressure loss on Mercruiser 140

    I did not see anything unusual with the pickup tube when I had it out. I also have a full tank and wouldn't that only be an issue if the leak was above the fuel level? I tried wiring in an electric pump and got the same result. Works fine for a while, then pressure starts to drop to zero on...
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    Fuel pressure loss on Mercruiser 140

    This is what I have attached to the valve cover and flame arrestor. Seems like I have had problems related to fuel delivery forever. Hot start problems. Now mostly surging after running for a while.
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    Fuel pressure loss on Mercruiser 140

    Thanks. I got the fuel pick up out without destroying it. Clean with no signs of obstruction. I was also able to stick an inspection camera into the tank. Also clean with no signs of residue or debris. I put a straight barb back on the pick up to see if there was something going on with it. Also...
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    Fuel pressure loss on Mercruiser 140

    Thank you all for the responses.
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    Fuel pressure loss on Mercruiser 140

    I did not remove the tube out of the tank. I’m pretty sure I’ll break it off if I try any harder to turn it. We’re it not for it being a fuel tank, I would have tried heating with a torch. Yes. Carter pump. With gauge tee’d in by the carb. Exact same symptoms before and after replacing pump...
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    Fuel pressure loss on Mercruiser 140

    Part of my unhealthy and expensive obsession of throwing new parts at my old boat. I should have mentioned that too. Brand new fuel pump.
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    Fuel pressure loss on Mercruiser 140

    Mid-1980’s Mercruiser 140. Been having fuel starvation issues. Installed fuel pressure gauge to help diagnose. Have sufficient fuel pressure when first starting, but then it drops to zero after running a while. I’ve replaced the line from the pump to the tank and from what I can see the inside...
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    Trouble starting when warm

    Overheating could have caused damage to heads. Have you checked compression?
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    Mercruiser exhaust bellow not staying on

    I have had the same problem on a 3.0 MR outdrive. Very frustrating. I just kept trying and finally got a good connection. Made sure to clean of the outdrive side really good after each attempt. I have also read about an exhaust tube that can be used to replace the exhaust bellows. Don’t have a...
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    Mercruiser 140 - low fuel pressure when hot?

    1984 Mercruiser 140. Problems starting when engine is hot. Recently replaced cylinder head with complete tune up. Fuel system is in good shape. Replaced most everything. I installed a fuel pressure gauge. On start up, it runs 4-6 psi. All good. As the engine warms up, pressure star gas to fall...
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    Engine or outdrive serial number to select correct water pump kit

    I’m sure to be ridiculed for this question, but when selecting an outdrive water pump kit, do I use the engine serial number or the outdrive serial number. This is for a 1984 Mercruiser 140 with the MR drive unit.
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    3.0 cylinder heads interchangeable?

    Anyone know if cylinder heads for a MCM 140/3.0 with casting numbers 2777770 and 2778954 are interchangeable?
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    Catastrophic failure? Mercruiser 140

    1984 mercruiser 140. Last year the exhaust shutter failed and the engine overheated. Replaced the broken exhaust shutter and the impeller and it’s housing. Boat started fine on the muffs. Went to the lake today and it ran fine for a half hour then slowly lost power and died. Was running a little...
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    Mercruiser 140 MR outdrive whine

    Just replaced raw water pump lower and upper housing and impeller. Making a steady whining noise. Have done this job on this boat a half dozen times without an issue. Everything went back together smoothly. Should I worry too much about it?
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    Fuel pump failure?

    Mercruiser 140, Alpha MR, serial #6853440. Fuel pump is three years old. Gave no warning signs and just quit working. Is that normal? Any recommendations other than replacing with stock? Electric?
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    Shift interupt switch?? - Mercruiser 140

    1984 Mercruiser 140, serial no. 6873947, Alpha MR I think the shift interrupt switch may be failing and cause an interruption in ignition when the boat warms up. Is there a good way to test the switch? The boat runs well on the water for about an hour an then develops a miss that I cannot for...
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    Ignition coil overheating - Mercruiser 140

    1984 Mercruiser 140, Alpha MR drive, serial no. 6853440 - I have been chasing an electrical problem for about a year now and am at my wits end. It is not a fuel problem. Symptoms are as follows: Boat starts and runs great for 30-45 minutes, then develops a miss. Miss can be made worse by...
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    Mercruiser 140 ignition coil voltage

    What should the voltage be when taken on both sides of the coil? I have read until I am blue in the face, including the sticky, and I am still confused. Admittedly, I get my cookies from the low shelf on this stuff. I get readings of 10.5 on the + side and 6.5 on the - side.
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    MCM 140, Alpha MR, 1984 - unable to locate source of misfire

    Very frustrating. After about an hour of running great, boat develops a misfire, made worse by turning on any electrical source (e.g. blower) and especially by activating trim. I have examined and cleaned wiring including cannon plug and related connections. The miss goes away momentarily but...
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    Mercruiser 140, Alpha MR - can't locate electrical miss

    I'm at my wit's end. Boat runs great for about an hour, then develops a slight electrical miss which turns into a major misfire causing the engine to shut down. Will re-fire and idle fine but will not accelerate. After another half hour or so, it will begin running normally. I am confident it is...
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