Shift Issue Mercruiser I/O

[JR74CJ5]

I have a friend with a Mercruiser sterndrive 120/140hp (the one with the loop on the top of the unit, not flat top) who is having some strange shifting issues. This forum helped me fix the same type of outdrive on my own boat.

His issue is that it will not lock into gear when the engine is running. I went to help him look at it yesterday. When the engine is off, the prop will lock using the shifter control arm. But like i said as soon as the engine is running using the contol shifter will not engage the outdrive into gear.

We are planning to replace the control shift cable, control shift box, and throttle cable anyway, but wondering if anyone has any ideas on what else this could be cause by...

Thanks,
JR

 

[NHGuy]

Re: Shift Issue Mercruiser I/O

Try just shifting it while the engine is not running, if there is any resistance & if the shift interrupter causes the micro-switch to open there's a fair chance the cable is too used to stay on there.
You can also test to make sure it has forward gear by running the engine (with water supplied to the lower unit) and having someone push the shift cable end toward the transom as the gear shift is moved into forward gear. If it won't click into gear you just have to check further, but that's the way the linkage works while it's on the boat.

 

[JR74CJ5]

Re: Shift Issue Mercruiser I/O

So basicly you're saying to manually shift the outdruve using the cable whil the engine is running to tell if the outdrive is working properly and in that case it would be from the shift plate forward (the control box / throttle and shifter cables)?

Thanks
~ JR

 

[Bondo]

Re: Shift Issue Mercruiser I/O

and in that case it would be from the shift plate forward (the control box / throttle and shifter cables)?

Ayuh,.... My guess is it's the Lower shift cable, Not the forward control cables...

 

[JR74CJ5]

Re: Shift Issue Mercruiser I/O

You think it would be the lower even though it locking the prop with the engine not running?