jerking at high speed

[mrsvt99]

I have a 115hp Johnson outboard. Recently the side of the gearcase blew the side out, and we replaced it with a new one. Ever since then when it gets to top speed it starts jerking about every 10 seconds. It's just a really quick and sudden jerk. We have adjusted the piece the puts the gearcase all the way in gear, and it still seems to do it. It takes off fine until you start to trim it up and then it starts doing it. We have adjusted everything we can think of. Could it be something in the engine? It never did it before we changed the case. Any help would be appreciated. Thanks.

 

[R.Johnson]

Re: jerking at high speed

You have a classic example of a forward gear, clutch dog failure. The shift, or "clutch dog" is jumping out of engagement with the forward gear. More than likely, they both should have been replaced when you replaced the gearcase. Before! the shattered forward gear went out the side of the case when it shattered from the shock of engagement.

 

[R.Johnson]

Re: jerking at high speed

Did you check the shift linkage after repair?

 

[mrsvt99]

Re: jerking at high speed

I put a completely rebuilt gearcase back on the boat. The parts in it are new so there should be nothing wrong with the case. My friend said that maybe the shift linkage should be re-adjusted to make sure that it is set up properly.

 

[alden135]

Re: jerking at high speed

Did you measure and correct the shift rod height per oem specs? Height is critical for proper operation.

 

[mrsvt99]

Re: jerking at high speed

I am going to ckeck that and make sure. When I put the gearcase on I didn't check to make sure that everything was in the correct position.

 

[R.Johnson]

Re: jerking at high speed

You have to have that shift rod, and linkage correct. That dog jumping out of engagement will give itself, and the forward gear a real beating.

 

[Joe Reeves]

Re: jerking at high speed

What is the model number of that engine?

 

[mrsvt99]

Re: jerking at high speed

The model is J115PLEE