Odd reverse problem

[afd2131]

Starting off, 1991 Force 120 HP outboard, with a recently rebuilt lower unit including a new clutch dog. The issue is when you first start the engine ( cold start) and put it into reverse, the engine rev's up, but it does not engage the gears at all ( reverse only, forward is fine). After the engine warms up a bit and is run, shift into reverse again and you hear a somewhat grinding noise like the gear is trying to engage, but still no reverse. After a lengthy run, you shift into reverse, still a little grinding, but the gears engage. Any thoughts on this? Gears and clutch dog are all recently replaced.

 

[Jiggz]

You need to mechanically "zero" the shift linkage. There are two sections on this called the upper rod and the lower rod shift linkage. First disconnect the two and then manually pushing down and pulling up on the lower shift rod will tell you the extent when the gears engages. Push down all the way on the lower shift rod and then make sure the gear is engage by trying to turn the prop. If it engaged, it should not move freely. Mark the shift rod with a marker pen. Do the same when you pull up the rod and making sure the gear is engaged. Mark it again. The zero is the mid point of the two marks. Now connect the upper shift rod, place the control lever in neutral, the lower shift rod should be positioned at the mid point mark. Go to forward and then also in reverse, and the corresponding marks you made earlier should be indicated on the lower shift rod. If not, make an adjustment which is located just below the carbs. If you follow where the upper shift rod goes into the lower cowling, you can't miss the adjustment screw.

Note, a little bias on the fwd shift is usually desired to ensure it does not slip not to mention it is the most common used position. When shifting into gear be a little snappy and never ease the handle in resulting in gears grinding. This will prevent premature wear and tear on the clutch dogs.