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    mercruiser 7.4 mpi can't figure out the ratio

    So, my opinion on why I’m getting Low compression is either a value is left stuck open or the pistons rings are bad. How can I figure it out?
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    mercruiser 7.4 mpi can't figure out the ratio

    They were not that Clean very all of the had a little bit of carbon on them. And the water would go in the chamber if the head gasket is blower? And If the value it stuck I would I be able to see it after removing the head ?
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    mercruiser 7.4 mpi can't figure out the ratio

    When I hit the old drive got caught up with do object in the water it was sudden causing the upright lower shaft to snap. Can that be a cause of why I’m getting low compression on cylinder 4 ?
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    mercruiser 7.4 mpi can't figure out the ratio

    Haven’t had water leaking in the chamber. Wouldn’t the spark plug look a bit rusty? They are look the same.
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    mercruiser 7.4 mpi can't figure out the ratio

    Hi, I did a compression test on the engine the Piston #1 -150 psi #2 - 150 psi #3 - 150 psi #4 - 90 psi #5 - 140 psi #6 - 160 psi #7 - 130 psi #8 - 150 psi Not sure if because piston 4 has 90 psi making the boat not getting the speed. what did you think?
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    mercruiser 7.4 mpi can't figure out the ratio

    No luck finding the number tired removing the paint too also.
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    mercruiser 7.4 mpi can't figure out the ratio

    I know what you mean it really doesn’t make sense
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    mercruiser 7.4 mpi can't figure out the ratio

    The tach is working I also think I’ll notice if the engine is revs higher than usual. Do you think the new drive is paired up with a different ratio lower unit seen in the chart I posted previously can it be a faulty drive Sometimes I get a hard clunk with changing gear to forward and reverse...
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    mercruiser 7.4 mpi can't figure out the ratio

    Not getting a hold of them
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    mercruiser 7.4 mpi can't figure out the ratio

    Yes prop are good I would have a vibration if they were bad. Also I since I was having this issue I tried going full throttle at once shot and the boat was more slower getting to plane but eventually reach to plane. I remember when I bought the boat and went for a test drive the previous owner...
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    mercruiser 7.4 mpi can't figure out the ratio

    Yes I’m using gps speed and also download an app to tell my speed to make sure. Not sure if I have a different lower ratio for the top
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    mercruiser 7.4 mpi can't figure out the ratio

    yes 4800 rpm 20 mph the motor doesn’t over rev. Compared to have the old drive everything’s runs the same except I’m not getting speed like before and this drive lashes into forward and reverse especially when I’m docking the boat changing gears fast.
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    mercruiser 7.4 mpi can't figure out the ratio

    Yes I would get between 25-26 mph at 4000 rpm The new drive at 18 mph at 4000 rpm it gets me right at plane. with the old drive max rpm and I would get 32 mph and now with the new drive I get 20 mph.
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    mercruiser 7.4 mpi can't figure out the ratio

    What ratio do you think I need for the boat and engine?
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    mercruiser 7.4 mpi can't figure out the ratio

    Thanks I’m in the process of getting on to them.
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    mercruiser 7.4 mpi can't figure out the ratio

    Thanks I have 22 pitch props right now with the 2.20 :1 I’m getting the rpm same as before but the speed is lower. I’m not sure on the ratio of the outdrive that was on before but, I counted the drive tooth and I have 23 so,Im guessing there was also a 2.20:1 gear ratio before. But not sure why...
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    mercruiser 7.4 mpi can't figure out the ratio

    hi, I already have the outdrive off the boat and I tried that method and I got 2 and about a 1/4 more turn of the shaft that goes into the engine. looks to be 2.20:1 ratio but, someone is also saying that it can also be 1.81:1 diesel I doubt it though. Shouldn't mercruiser 7.4 MPI be running...
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    mercruiser 7.4 mpi can't figure out the ratio

    Hi, I have a 2001 wellcraft 270 coastal with a mercruiser 7.4 MPI with a bravo 3 outdrive 22 pitch prop. Late this summer the lower shaft upright shaft snapped and I couldn't tell what ratio I had so, I took a shot buying a bravo 3 gear ratio 2.20:1 and the guy had the same engine but, his...
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