Johnson 18hp wont stay in forward gear.

[hondarider188]

I have a Johnson seahorse 18hp. I just recently went through the lower unit and and replaced the impeller and prop seal. when i took the lower unit off i had difficulty getting the shifting rod to disconnect. Once i had it out though the impeller and prop seal were easy to replace. when I did the prop seal though i had to remove the entire gear assembly and on reassembly i lined the slots back up and it seemed to sit in place fine. as for the clutch dog When i connected the shifting rod i set the tabs on the clutch dog horizontally because I doesnt look like that should really matter anyway. then when I went to reinstall the lower unit I had difficulty getting the shift rod to go into the connector all the way, then I had issues with it not going into neutral because of the lever but i fixed that by getting the rod to go into the connector farther. but for the shifting rod im still not confident it is correct since the motor wont stay in forward gear when running. but im not sure what to do with it or really how it is supposed to be properly set up. And this just happened after i worked on the motor before it shifted fine.Also it will pop out of gear and into neutral at idle after a few seconds of running, and giving it throttle only makes is happen a little faster. thanks

 

[F_R]

No Title

Your story certainly suggests a totally worn out clutch dog (the "tabs" you called it), and mating forward gear. Faces of the dog and gear must be straight and square, no rounding off allowed. Only thing suggesting otherwise is you claim it worked before you took it apart. In any case, you are going to have to go back into it to see what is wrong, or what you did wrong.

The dog in the picture is totally worn out, long past due for replacement.

 

[gm280]

I concur with F_R as well. There is a chance that you are not fully latching up the clutch dog into the gears all the way as well. But either situation, it looks like you will have to go back into the lower section again...

 

[hondarider188]

ok I will open it back up and take a look. Im still not sold on it being the clutch dog though just because i had some issues with the shifting rod going back together and im not sure that its right. Could you also let me know how the shifting rod is supposed to be and ill check it out too. A picture would help. thanks.

 

[F_R]

The shift rod is pure simplicity. There are two notches in it (actually one in the upper rod and one in the lower rod). There are two bolts in the brass shift rod connector. Each bolt must pass through the corresponding notch in the shift rod. There is no "adjustment", the bolt passes through the notch and that's it. Of course if you didn't get the bolt through the notch, that's a different story. If you are having trouble getting the rods entered into the brass connector, take a big screwdriver in the slots on the side of the connector and open it up a bit. The bolts will squeeze it tight again on the rod.

 

[bwkre]

No Title

F_R has it right although a model & year might help. Attached is a pic of the lower shift rod & connector for a 61 18hp. The shift rod pins to the cradle in the gearbox so it would be hard to make a mistake there. The top end of the rod has a machined groove. The rod must go into the coupler far enough for the bolt to end up in the groove. Since the forward gear is at the back of the gearbox the shift rod must be lifted to engage forward. If the shift rod is not installed correctly it will not be able to move upward far enough to engage forward fully. I would take the little side access plate off first to confirm the linkage connection. The clutch dog does not have detent balls and a spring to hold it in gear on the prop shaft so it relies on the upper shift handle to hold it in gear. So if it doesn't shift fully it will easily pop out of gear because the shift handle will not be fully seated in forward position of the shift lock arm. You could shift into forward and visually see if the handle seats in the shift lock arm. It is located outside the cowling below the shift handle. Be sure to rotate the prop as you shift. That's what I see anyway.

 

[78 mckee]

I would also check the forward prop shaft bearing (I believe it is actually a bronze bushing in this case). A severely worn bearing will allow the shaft to move enough to disengage the clutch dog under load.