Re: 1986 OMC 800 shift problem...need help
To determine if it?s the cable I would completely remove it from the shift box, pull one end as far as it will go and see if it goes into forward, which it should, then pull the other end as far as it will go and see if reverse engages. If reverse does engage then your nominal neutral setting is probably out of whack. The cable is being pulled far enough to go into forward but not reverse. This can be easily adjusted if it is the case. Hopefully it is. As far as the switches go it does not affect the engagement of the gears as much as it does coming out of gear. The micro switches turn the interrupter off, so pushing them won?t stumble the motor. The third switch attached to the arm with the little cam is the switch that turns the ESA on. You can turn the motor on, push the third switch plunger and she should go into stumble mode, then you can push one of the micro switch plungers and it should shut off. One micro switch is for shutting off the ESA once you are in forward gear and the other is there for once you are in reverse.
Now let?s turn our attention to the dog clutch if you find the cable is working fine. The dog clutch is a stout, hollow, sliding cylinder splined to the propeller shaft, with teeth cut into each face for engaging the adjacent gears (forward and reverse). The teeth on the clutch dog resemble the top of the "rook" piece or the castle in chess. Each side of the dog clutch has this appearance. Immediately adjacent to the clutch dog on the propeller shaft are gears that spin freely on the shaft. These gears mate with a third gear that is driven by the engine, thus these gears are always turning while the engine is running. These gears turn in opposite directions. The stern drive is in neutral when the clutch dog is between the nearby gears; the drive engages forward or reverses by sliding the clutch dog into the appropriate gear that turns with the engine. This is done via a shift rod that is operated by the shift cable.
There is no "clutch," as you find in an automobile. Gears engage with a jolt. The shift interrupter kills a few cylinders in the motor to lower the RPM and torque to allow this jolt to be as less of a jolt as is possible and allow to the clutch to engage more smoothly.
My guess is that the reverse side of the dog clutch, the castle top shaped notches has broken. They are fine on the forward side since you can go into forward. Going into reverse you wouldn?t hear the momentary grind as the clutch attempts to engage into the reverse gear. It?s possible it?s the reverse gear itself (notches stripped) but I?m leaning towards the clutch being broke.