15 horse Johnson jumping out of gear

[Polar Bear]

I have a early-mid 80's 15 hp. that jumps into neutral at full speed. It works fine at trolling speeds but shortly after nailing the throttle it will pop out of gear causing the motor to race. Any thoughts?

Polar Bear

[Paul Waldowski]

Moving to Equipment Forum

[Valv]

Did you check all the linkages for binding ? Also checked if there's oil in lowr unit.

If all the mechanism from lever to lower unit rod is free, and doesn't cause any problem, it might be the clutch dog inside gearcase, not expensive but very labor intensive, if you take it to a dealer it might get a little steep.

[Rainman]

I would also say it is your clutch dog. It is quite easy to do. I just did mine this last summer and it only took a couple hours if that!

[Surface Tension]

I had a 25 hp jump out of gear at full speed, kinda took me by surprise. I would look at the shift linkage coupler first. You'll see a small rectangular cover mid way on the side of the drive. Take it off, the coupler is brass with 2 bolts that hold the ends of the shift linkage. Check to see if both ends are seated in the coupler all the way and the bolts are tight. If they are then you shift dog is wore. While your replacing the shift dog you may as well replace the impeller. You'll have to remove the lower bolt on the coupler in order to free up the lower unit. Then get yourself a manual.

[hydro]

Your problem is the shift dog, which by itself is easily replaced but is not usually the whole problem. If the symptom is that the motor slips out of gear and immediately back in (with a clunk), and this happens when power is applied, the gearcase needs to be disassembled and looked at.

If you're up to it, pull the gear assembly out and carefully examine the edges of the shift dog ears. If they appear at all worn or rounded, take a look at the recesses in the mating gear and look for wear there as well. Just replacing the dog with a worn set of gears will buy you a little time but the problem will come right back. Replace the prop shaft seal while you have things apart.

The cause of this problem is gingerly easing the shift lever into gear which you can hear as a clicking noise during the shift. The dog ears rub on the gears and everything takes a beating! Always shift with a snap into and out of gear to prevent the problem.