MC-1 No Reverse

[Cresco750]

Today when I was coming into the wharf after a mornings boating I was attempting to maneuver in to tie up when all of a sudden I was unable to select reverse. As I shifted the lever rearwards all I got was more throttle, while the drive stayed in forward gear. A few very anxious moments, especially since I had a ten knot wind from behind, and a tight space in which I was trying to maneuver, and some numpty pulling out in front of me in his forty-something foot launch.

Symptoms: the drive will shift from neutral to forward smoothly. However, if the engine is running the drive will not come out of forward until I switch the engine off. I can then restart the engine and it is in neutral. Once the engine is idling in neutral I can't select reverse gear; all that happens is the revs come up. The shift lever itself seems to still have unimpeded full travel.

The boat has only done around 25 hours since a new lower shift cable was installed , and up until today it has shifted flawlessly.

Where should I start?

Cheers

 

[dubs283]

Re: MC-1 No Reverse

with engine off, not running have a helper shift the remote at the helm from neutral to forward to nuetral to reverse while watching the shift plate

you should see the shift plate assy moving from neu to fwd to neu to rev, corresponding with your helpers movements at the helm

if you do not see this happening, there is an issue with the shift plate or the remote shift cable

if everything appears normal, the issue is with either the lower shift cable, the shift cable adjustment, or the drive

you can disconnect the lower shift cable from the shift plate assy and check if the drive is shifting as well

 

[Cresco750]

Re: MC-1 No Reverse

Thanks Dubs. I will follow your advice tomorrow.

Cheers

 

[Cresco750]

Re: MC-1 No Reverse

Ok, so this afternoon I did a bit of troubleshooting with my able assistant (AKA: my lovely wife at the helm;
Cables and shift plate appear to be moving ok in both directions. I then disconnected the lower cable from the shift plate and my assistant pushed and pulled the cable while I checked at the prop for gear selection. The prop / gear was easy to lock in forward gear (and a positive ratchet overrun), neutral was OK, however we were not able to get any hint of reverse gear to engage. I could hear the odd gear catching as the prop was rotated but not enough to lock in.
I checked the length of the lower cable adjuster at the shift block as per the manual as being 6 inches, so it would appear that all is ok there?
I did note that the shift assist switch didn't move while my wife was cycling the control at he helm; could this explain why I all of a sudden was not able to get out of forward gear while the engine was running? I'm just trying to remember whether it is meant to move at all if the engine isn't running?

One point I will mention is at when all this first happened and I was trying to maneouver over into the dock, I was forced to select from forward gear to neutral-to-reverse quicker than I normally would as I had to take evasive action to avoid the guy in the forty footer pulling out in front of me. Reverse selected ok, but the gears did sound like they crunched all title harder than they normally would if they were given longer to stop rotation before selection. Following this episode the reverse has been elusive. Could this indicate that there is a problem down below?

Any other suggestions before I pull the drive off and try selecting the gears directly from the shift lever on the outdrive?

Cheers

 

[Eric 3.7LX Alpha 1]

Re: MC-1 No Reverse

There is a chance that there is some crud behind the shift lever in the bellhousing where the cable is, preventing the travel in the cable you need to engage reverse.

Attached is Fishermarks Pic which shows the shift lever and cable end, Right behind is where to look.
With only 25-hours on it, hard to believe but I guess it's possible.

 

[dubs283]

Re: MC-1 No Reverse

time to pull the drive and inspect further

as mentioned, there may be something physically preventing the shift shaft from rotating properly

could be the shift cable is worn and binding up not getting full travel - this is most likely

the drive needs to come off to change the lower shift cable anyways - thaty way you can shift the drive without the cable and check to make sure everything is working there

and yes, the shift interrupt switch will only work/engage with the engine running and a load on the prop (in the water)

to see if it works, with the engine running and in neutral, just depress the arm and if the enigne dies, the switch works - you can lightly bend the arm to adjust it if necessary

 

[Cresco750]

Re: MC-1 No Reverse

Shift cable, and shift shaft bearing/bushing and seal have only just been replaced within the last 25 hours so I'm assuming it isn't either of those causing the problem (at least from a wear point of view)?

Cheers

 

[dubs283]

Re: MC-1 No Reverse

Shift cable, and shift shaft bearing/bushing and seal have only just been replaced within the last 25 hours so I'm assuming it isn't either of those causing the problem (at least from a wear point of view)?

probably not worn but possibly installed incorrectly

another thing to check is the cable routing, there is a correct way to do it - if it is installed incorrectly it can cause premature failure

 

[Cresco750]

Re: MC-1 No Reverse

Thanks I will look into it. I did the cable replacement myself, ensuring that it was routed the same as the one I took out, but who knows.

Cheers

 

[dubs283]

Re: MC-1 No Reverse

ensuring that it was routed the same as the one I took out

there is no guarantee the old one was routed correctly, manual #14 has pictures of how V-8 engines must have the cable routed

#14 does not pertain to your specific drive but the picture of cable routing in it is correct for your V-8 engine

 

[Cresco750]

Re: MC-1 No Reverse

I've just had a chance to further investigate the problem of lack of reverse. I found that the shift lever 'shoe' had somehow disengaged from the stainless steel channel coupler on the bottom of the upper shift shaft. By wriggling it I was able to get the two reingaged but found that I had to hold the shift lever up with my finger to the shift shaft otherwise it could drop down again enough that it would disengage under a small amount of pressure. With it all engaged I was able to verify that forward / neutral /reverse all locked in / ratcheted as they are supposed to.

The lower shift shaft which protrudes out of the top of the lower box as a spline can be pulled up and down by about quarter inch, however the shift lever in the upper box housing is very sloppy and I can't see anything which is meant to stop it from dropping down (I can see the washer / split pin stopping it from going up too far).

Is upwards pressure from the lower shift shaft meant to keep the shift lever engaged with the upper shaft, or is there something else that I'm missing?

How much of the lower shift shaft should be sticking up above the seal? Hopefully I can eliminate this being somehow forced down into the box too far?

Cheers

 

[dubs283]

Re: MC-1 No Reverse

there is a washer that sits on top of the shift shaft seal bushing, you access it by splitting the drive halves

have you had the lower half of the drive off to service the water pump or other items??

without the washer on top of the seal bushing the shift "foot" will drop down about a 1/4" and not engage with the fork in the bell housing

 

[Cresco750]

Re: MC-1 No Reverse

Ah ha, you're right! I forgot about that washer, and I now realize its purpose. I recently had the local mechanic do some unrelated work n the outdrive and maybe he neglected to put that washer back in? I didn't notice it when I split the two halves.

 

[dubs283]

Re: MC-1 No Reverse

you may want to replace the bushing and seal too

the shift foot will wear the top part of the seal without the washer in place

 

[Cresco750]

Re: MC-1 No Reverse

you may want to replace the bushing and seal too

the shift foot will wear the top part of the seal without the washer in place

Yip, just had that done about twenty hours ago by the mechanic because the seal was leaking. This is when he forgot to reinstall the washer, and its just been through sheer luck that I haven't lost reverse earlier. I had the drive apart to do the water pump mid last year and deffinately remember putting the washer in then.