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Thread: 125 force, any good?

  1. #11
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    For those of you out there who've never seen that 5 banger up close, it has three IDENTICAL carbs. The top and bottom pairs of cylinders breath through one carb a piece, where that lonely center cylinder has a carb all to its own. Somehow that setup actually worked but, when the throttle was whacked open, one suspects the center cylinder was 'helped' up to speed by its four brothers!

    Jeff

    PS: I have a few of these carbs and a reed assembly or two if anyone needs them. Was going to use them to make an external reeds triple Merc 700. Might yet.

  2. #12
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    Default 5-cylinder

    Quote Originally Posted by David Mason View Post
    I rebuilt one for a friend this last summer. I have to say, parts are not easy to come by for that thing. Bearings are easy of course, as you can have them made or to spec at any good bearing shop. But pistons... and seals, etc.... were not easy and expensive. Some outfit was selling a rebuild kit, it included needle bearings, rings, pistons, and seals and was around $800.00.

    Very easy engine to work on though, wiring was pretty straight forward, and no suprises. Well one suprise, I had never seen a 5cyl before so I thought it was pretty funny.
    But the sound is beautiful - a bit like a four stroke V10, especially with the lower unit removed. Plus, the 5cyl might be regarded as a collector`s item.
    mercruiserparts.com still have most of the spares at reasonable prices, and for the post `96 engines CDI can help with the (Mercury) electronics. Other parts can be gotten off e-bay.
    Didn`t make any progress with pulling the 120hp four with adapter housing off the leg this weekend. Discovered two hidden Allen head bolts at the front-difficult to get to.

  3. #13
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    Now I know and would like to advise all mixers and matchers like me:
    the post `96 4-cyl Force powerheads coming off the then Mercury (120 to 200hp) tower/gearfoot assy will NOT fit the older Force and Chrysler driveshafts, unless major machine-shop work is done. The Merc driveshaft has a larger dia and a different (coarser) spline. It could only be accommodated with the `96 and later revised (larger dia mains and big ends) 4-cyl crank.

  4. #14
    Team Member RForeman's Avatar
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    Default I raced for Force Outboards

    I raced for Force Outboards several years. Won many races in the F-100 and Mod 110 classes in OPC and placed 2nd at the Nationals in Kankakee in 1988 with a 125 Force.
    The 4 cylinder is a cross flow motor and will not turn high RPMs. It will provide very good horse power at 6,500 -7,000 RPM. Carbs and exhaust are key to making the motor run good.
    We never had an ignition problem and ran fixed timing.
    -Roddy

  5. #15
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    Quote Originally Posted by RForeman View Post
    I raced for Force Outboards several years. Won many races in the F-100 and Mod 110 classes in OPC and placed 2nd at the Nationals in Kankakee in 1988 with a 125 Force.
    The 4 cylinder is a cross flow motor and will not turn high RPMs. It will provide very good horse power at 6,500 -7,000 RPM. Carbs and exhaust are key to making the motor run good.
    We never had an ignition problem and ran fixed timing.
    -Roddy
    Finally - from the man in the know. Many thanks for your contribution, Roddy. The rev range you are mentioning we would not have dreamed of with the old Chrysler in the late `60s. What flywheel did you use? and what porting would you suggest for 6500 max?
    rgds, Wolfgang

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    Team Member JohnsonM50's Avatar
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    Quote Originally Posted by wolfgang View Post
    Finally - from the man in the know. Many thanks for your contribution, Roddy. The rev range you are mentioning we would not have dreamed of with the old Chrysler in the late `60s. What flywheel did you use? and what porting would you suggest for 6500 max?
    rgds, Wolfgang
    The RPMs are also dependent on prop choice, weight & drag.

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    Quote Originally Posted by JohnsonM50 View Post
    The RPMs are also dependent on prop choice, weight & drag.
    This venue being BRF, we are talking racing speeds here. NU (1650cc=100ci racing runabout as per UIM), predecessor of ON until the cats came.
    rgds, W

  8. #18
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    I didn't know west bend made a 100hp outboard Was this a test motor?

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    Sam Cullis Mark75H's Avatar
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    Not 100hp, 100 cubic inches or less. All of the 4's are less than 100 cubic inches.
    Since 1925, about 150 different racing outboards have been made.


  10. #20
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    That 5 cylinder had a unique intake arrangement (that apparently worked okay): The top and bottom pair of cylinders breathed through the same carb as the center cylinder did all alone.

    Jeff

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