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Bearing Cage O-ring? 87 Force 125

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  • Bearing Cage O-ring? 87 Force 125

    Here's a minor mystery that someone may be able to clarify:

    Is there an O-ring for the bearing cage assembly on a '87 Force 125 "B' model?

    There is no reference to it in the Clymer or Seloc manuals, and I don't see it in the Crankshaft and Piston Parts diagram on Crowley Marine's site.

    Both the upper and lower bearing seals where included in the Power Head gasket kit I ordered but there was no O-ring, so I didn't even think of it until I was reading through the Mercury manual for this motor.

    I'm thinking this may be a bad reference in the Mercury manual, but I just want to be sure I'm not missing anything.

    It is mentioned in the following section (in red) regarding the crankshaft bearing cage assembly:

    Power Head Reassembly.
    1. Reassemble and install upper crankshaft bearing cage.
    2. Clean gasket surfaces on bearing cage and power head.
    3. Position crankshaft bearing seal with garter spring on bore of crankshaft bearing cage (major sealing lip in). Figure 52.
    4. Press seal in bore of bearing cage using seal installer, Special Tool No. T 8903.
    5. Install new bearing cage seal (O-ring) on bearing cage assembly.
    6. Install seal protector on top of crankshaft. Special Tool No. T 8927. Apply grease to lips of crankshaft seal. Special Tool No. T 2961.
    1987 Bayliner Capri
    1987 Force 125

  • #2
    Re: Bearing Cage O-ring? 87 Force 125

    I'm not an expert but I've done several 1980's era 125 HP Force engines. I've never seen an "O" ring on the bearing cage assy. I don't think Mercury was in the picture yet in the 1980's. They didn't start to get involved until sometime in the early - mid 1990's. I don't think the statement you highlighted in red applies to the Force engines.

    The only seal that I know of that is around the cranlshaft bearings is the crankcase seal. It's a metal ring that resembles a piston ring only much smaller. It actually goes around the crankshaft to seal each crankcase cavity from each other.


    • #3
      Re: Bearing Cage O-ring? 87 Force 125

      The Force three and four cylinder engine blocks (with the possible exception of the Mercury built 70 and 75) do not use and never did use a lower bearing cage.

      If used, this cage holds the lower ball bearing in position, thus locating the crankshaft, and there is a needle bearing on the top of the crank. Mercury does use a lower bearing cage and it does have an O-ring seal. It is held into the bottom of the block with four 1/4 X20 bolts.The Chrysler 55,60, and 65 used a lower bearing cage just like Mercury and it also had an O-ring seal.

      NOW: Some Chrysler engines and possibly Force engines (Offhand I don't remember if Force did use them at all) did use an O-ring to seal the upper bearing cage. If it did use an O-ring, then there would be a groove in it. Otherwise you just "shmutz" it up with a little of the Locktite red crankcase sealer or black silicone RTV and bolt it in place.

      SO: Mercury was probably covering all bases and it may not have been a typo.


      • #4
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        Re: Bearing Cage O-ring? 87 Force 125

        Addendum: On the early Chrysler engines, the groove for the upper bearing cage O-ring was in the top of the block. I don't remember any Force using an O-ring since by then the bearing cage/stator carrier was Prestolite ignition and held with five allen head cap screws.