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  1. #1
    Member Axhammer's Avatar
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    1998 Mercury 200 EFI prop swap…will it work?

    This may be a stupid question, but I don’t have a lot of experience with this stuff.

    I removed the Tempest three blade prop from my 1998 Mercury 200 EFI. The diameter of the Tempest matches the diameter of the lower unit.

    I was planning on installing a spare four blade prop, while I ship the tempest to Mark C for rework. When I slid the four blade prop on the splined shaft, I noticed the propeller diameter is smaller than the lower unit, where the two meet. I didn’t notice this before I removed the four blade prop from the 1989 Mercury 200 it was on. I slid the four blade prop back on the older 1989 Mercury 200, and sure enough, the prop diameter is smaller that the lower unit where the two meet. This tells me the four blade prop will work on my newer 1998 Mercury 200 EFI.

    I understand the four blade prop will accelerate out of the hole faster, AKA better hole shot, but the top speed will suffer slightly.

    I wonder what would happen if the four blade prop actually matched the lower unit diameter like the Tempest does?

    I cleaned up my boat and covered it yesterday, with the intent of not using it again until spring. I figured I would install the four blade prop, but then I noticed they have a different diameter.

    my question is…Will the four blade prop with a smaller diameter work on my 1998 Mercury 200 EFI? I’m guessing Yes, it will work, since it fits the same on the older Mercury 200.

    For now my boat is parked & covered under a carport for the winter, without a propeller on the engine.
    Attached Images Attached Images
    1998 Ranger R-91 Intracoastal
    1998 Mercury 200 EFI (S/N OG680217)
    Tempest A45 25P (no jackplate)

  2. Member Axhammer's Avatar
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    #2
    As long as I have a thread on props, I may as well ask another question I have. What does everyone ship their props in? I would guess most folks box them up in a sturdy cardboard box and ship them. My props are heavier than I expected. I have shipped carburetors on cardboard boxes, but I make sure they have a lot of padding and even extra cardboard for protection. I would hate to get a freshly worked prop back, with shipping damage. Thanks is advance.
    1998 Ranger R-91 Intracoastal
    1998 Mercury 200 EFI (S/N OG680217)
    Tempest A45 25P (no jackplate)

  3. Member
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    #3
    The smaller diameter 4 bladed might be a Trophy prop or a Trophy Plus prop. You can buy a weed ring for these ( plastic or metal) that will fill the gap. If you don't fill the gap, you will get exhaust gasses passing there and onto the blades of the prop. This might cause slip.

    If the 4 blade prop matched the diameter of the Tempest it would be a Revolution 4 prop.

    I always keep the boxes from the company and use that.
    Last edited by Real L; 11-16-2021 at 05:30 AM.

  4. Member
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    #4
    The smaller hub 4 blade will work. As mentioned above, it may slip (blow out) as you break over on plane if it's venting too much. If the prop has PVS holes (hard to tell from your pic), plug 2 and leave the other 2 open and see what happens.

    I buy boxes, then cut a 1/2" piece of plywood or OSB that fits the box and put a 3/8 carriage bolt in the center. Put the prop over the carriage bolt and use a big washer and nut to hold it in place. Hope that makes sense.

  5. Member Axhammer's Avatar
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    #5
    I found a picture of the 1989 Mercury 200 with the Turbo four blade propeller installed, as it was when I bought the 1989 Astro boat. The prop had been on that boat for many years, and performed well when I bought it. The prop doesn’t have any vent holes.
    Attached Images Attached Images
    1998 Ranger R-91 Intracoastal
    1998 Mercury 200 EFI (S/N OG680217)
    Tempest A45 25P (no jackplate)

  6. Member
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    #6
    get an aluminum blow out ring, order it from Croxton, tell him what you have. It will make the prop work as intended and keep gases from going out around the prop, and keeps weeds out

  7. Im wishin I was fishin
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    #7
    plywood or osb get an empty box that gallons of paint came in good fit for most props