1998 Mercury Force 9.9 2 stroke thermostat

Discussion in 'Powerboats' started by Jimheal, Aug 27, 2025.

  1. Jimheal
    Joined: Aug 2025
    Posts: 2
    Likes: 1, Points: 1
    Location: Arkansas

    Jimheal New Member

    I have spent a ton of time online looking for info on this. All pics and videos show a small plate covering the thermostat near the plugs on back of engine. Don't have that. My pee tube comes out of a large plate just forward of the plugs/head and the plate is mounted with 12 bolts. The only 3 bolt plate is behind the fuel pump on the engine opposite side from the pee tube connection. Anyone have any ideas on this? Am I looking at it already? Thanks.
     
  2. sdowney717
    Joined: Nov 2010
    Posts: 1,600
    Likes: 118, Points: 73, Legacy Rep: 274
    Location: Newport News VA

    sdowney717 Senior Member

  3. Jimheal
    Joined: Aug 2025
    Posts: 2
    Likes: 1, Points: 1
    Location: Arkansas

    Jimheal New Member

    Well, apparently the "force" part of the description is the key. Instead of putting the thermostat up on the engine (like in that video and many others), they mounted it on the rear, well below the engine. They added a plastic block (1.5 X 2 inches) over it to hold it in place. Same as the Gamefisher model. Found it, corrected the problem. Engine now cooling as designed. Thanks
     
    sdowney717 likes this.
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