Page last updated July 17, 2008



Outboard Gear / Throttle Adjustments

I have noticed that my Mercury 650 outboard motor was shifting into reverse gear without properly locking in place / a little grinding, so I would have to push the lever a bit farther. I will go over how to adjust the gears so that shifting is the same for forward and rear.


Keep in mind, you may not find the exact spot easily, it takes a little of your time and should be done when you have 30 minutes to kill.

Here are the steps.

1. With engine off, remove cover and remove latch that holds the throttle and gear linkage on the left side of engine (viewing from behind engine).

2. Place gears in neutral, hand-turn the propeller in both directions and it should spin freely.

3. Place gear shifter in reverse and hand-turn propeller and it should only turn in one direction. It should catch the gear while you attempt to turn and lock; the flywheel should seem to move, if it slips or If it turns slightly in another direction, then you may need to adjust the linkage or the gear may slip and grind your gears.

4. With engine OFF, repeat procedure for forward gear and it should only spin in 1 direction and it should catch it securely..

When you have an idea of what is correct and what needs adjustment, then proceed to the next steps.

Please note: When you make adjustments, you are adjusting how far the lever pushes or pulls the gear. Any adjustment will offset the opposite gear. Make small but obvious changes.

Example: My reverse gear was not catching so I adjusted it and initially it fixed the reverse gear but then the forward gear would not catch properly. I adjusted too much....I had to play around with it until I found that sweet spot for both gears. You may have to do the same. The process is simple and if you think you will mess up, just mark the original spot with some spray paint so you know where to move it back.


Now that you know what gears needs adjustment, then proceed to the next steps.

1. With the latch removed exposing the throttle cable, remove the throttle cable from its postion with a phillips head screwdriver. It is attached near the throttle lever on engine, just loosen and you will be able to remove cable, don't remove screw because it will be hard to replace it (if you leave in place, you may not be able to remove the gear cable)

2. Now, remove gear cable by removing the circular barrel that has the cable going through it. The barrel is what you will be turning to adjust the gears. When you screw the barrel, it pushes or pulls the cable so that it has a different effect on the gear lever. Pulling the cable through the barrel will push the reverse gear further into locking position, pushing the cable back toward the boat will effect the forward gear and will reduce the catch into reverse gear. play around with, slight adjustements are better than large ones.

If your reverse gear is what is slipping, then you want to push the cable further out away from the boat. Screw the barrel so that the cable is coming out. This has the result of pushing the reverse gear further allowing it to catch.

If it is your forward gear that is not catching, then you want to push the cable toward the boat. Basically when you screw the barrel and place it back into position, the slight shift will position the gears in place.

You have to find that sweet spot, so put the barrel back into position, lock the gear cable back into the catch and test the gears to make sure they are catching.

If they don't work as they should keep fine tuning the barrel adjustments.



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