As a non expert, I'm just going by what your telling me. Hey
@Texasmark maybe so.e help.
You say everything works as it should and you have a right handed prop on the motor
Thanks for the intro but I can only try to help.
Force (Mercury Marine product) was initially a West Bend, then Chrysler, then early model Force...Mercury's low ball market entry, and later incorporating some of Mercury's parts/designs. I don't think it was ever intended to enter the up scale dual engine installation whereby you ran a L and R (counter-rotating) prop setup like their regular higher HP engines.
3 things cold be your problem: Linkage in the control box, or your lower unit was removed for servicing...like a water pump impeller change, and upon reinstalling the shift cam position didn't agree with the position of the remote control...a fairly common problem with do-it-yourselfers. or somebody tried to shift into R without the engine running or prop turning and damaged the engine shifter linkage.
Some older control boxes were built for multiple position installations and had cable entry holes on the top and bottom of the rear of the control. The position of the cables (top or bottom holes) determined the direction the center conductor moved when the shift lever was pushed in the opposite direction from the cable entry end.
I am not familiar with the Force lower unit as having had West Bend, and Chrysler (45 and 85 HP) engines but never having the LU off. I don't know if Mercury used their LU design when they went to the thru prop exhaust (later production) or not....and just what model of the Force you have.
If it were my engine I'd first disconnect the remote cable and grasping the connection pin in the engine where the center cable attaches, see if I could move the shifter arm through FNR positions......being careful when attempting to go into R without the engine running, to manually turn the prop so that the cogs and slots can line up and engage. If that doesn't work, the shifter cable in the engine is damaged or the lower unit shifter stub was in the wrong position when reinstalling the LU.....if a Mercury design or similar shifter setup. Otherwise have a look at the control box setup. Some history would help as would a service manual for that engine.
Faztbullet is better suited to answer that question as he is in the business and is a certified mechanic as are a few others who frequent the site, Chris1956, Racerone, Dockside Marine Services, to name a few.
