Mercruiser Alpha 1 Won't Shift Into reverse

[Zorrick]

I changed the impeller on my Mercruiser 4.3 and now it no longer shifts into reverse.

Engine Serial: 0C676911

Drive Serial: 0C818989

This was done right before it was put in storage and I never actually knew the reverse was shot on it then.

Now I've taken the boat out and I couldn't figure out what the issue was. The reverse became incredibly hard to shift into, and it would die immediately (due to shift interrupt). I wasn't quite sure what was going on and I definitely cranked on the shift cable to jam it into the reverse gear, putting probably 5x amount of pressure normally required to shift.

I changed by impeller by dropping the lower I think it may have been off by 1 spline when I put it back together (although I was fairly certain I hadn't!)

In full reverse you can see the shifter turning to around the 2pm position, (See Pic 3) whereas I thought it needed to get a little bit further.

Now I can get the boat to shift smoothly and not engage the auto shut off - but with all the adjustments I've never once been able to get it to shift all the way into reverse, it is very close but never quite gets there.

When I disconnect all the shift cables from the motor - and use the shift cable by hand, I still cannot pull hard enough (even with leverage) to get the shifter to go into reverse gear.

The shift cable itself doesn't seem worn out, and the previous owner said he changed it out a few years ago. Before I take it to a shop, should I just go ahead and replace the shift cable? Is it possible that me yanking on it has stretched the cable so much?

When I change the cable, should I bother to change the bellows at the same time? Since I'm doing the cable, is it worth while I have things apart to do other things?

Would this part be applicable?

http://www.sterndrive.info/alpha-one/shift_cable_assembly.html

I've read as many forum posts and all the suggestions as far as adjustment, pretty sure I've tried everything at this point including step by step from the manuals twice. I must of stretched the cable, right?

 

[Rick Stephens]

I would always recommend you pull the entire drive and split them on the bench. Besides, there are annual maintenance items such as greasing inspecting u-joints, gimbal bearing ,alignment and whether there was any leakage into the bellows. Makes it a LOT easier to drop the upper onto a lower with the lower in forward and the upper shift shoe facing forward.

You need to drain, pull the drives apart and make it right.

Before doing that though, I would recommend you detach the lower shift cable at the engine end and hand operate it. See if it is glass smooth or not. That will tell you better whether it needs replacing.

RIck

 

[Bt Doctur]

Remove the drive , disconnect the cable inside the boat, push shift slide in all the way. It should bottom out. If not crud/mud/debris has been compacted in the slide. Remove the setscrew, remove the core, clean with a drill bit

 

[Zorrick]

Thanks for the thoughts so far, I only have access to the boat once a week right now. So quick testing can be difficult.

Rick - I had previously detached the cable and did find it to be quite smooth, I can't recall right now exactly how smooth though. So if I find it to be rough - that would be an indicator it needs to be replaced?

On my model, with the lower shift cable detached at the engine end - I can pull as hard as I can but it will not pull far enough to turn the upper shift shaft into reverse (2pm position) so I'm curious if anyone would know if that would indicate it was the shift cable.

Bt Doctur - Interesting idea - sounds like a ton of work to take the drive off for the test though, I've never done it before perhaps its not as daunting as it sounds though. Any idea how long that should take?

There was no shift cable bellows - I noticed, and it was in salt water somewhat regularly when I first got it. Wondering if that would impact it a lot.

Could anyone tell me if that upper shift shaft is turning enough? And what would be the cause if its not? (Assuming cable is not out of adjustment)

 

[dubs283]

sounds like a ton of work to take the drive off for the test though

pretty easy to pull/install an alpha drive. if you are serious about working on your own boat you should get very used to doing this

There was no shift cable bellows

huh?

 

[poconojoe]

Without a shift cable bellows, I believe your boat would have taken in a lot of water. Probably would have sunk.

 

[Rick Stephens]

On my model, with the lower shift cable detached at the engine end - I can pull as hard as I can but it will not pull far enough to turn the upper shift shaft into reverse (2pm position) so I'm curious if anyone would know if that would indicate it was the shift cable.

No. You need to remove the drive, drain the drive, split the cases and put the lower into forward gear - and keep there. Then while keeping the intermediate shift shaft facing forward you reassemble.

While the drive is off, check the bellows, grease the u-joints, inspect gimbal bearing. Then check alignment before reinstalling the drive. Those are annual maintenance items that will keep you from breakdowns in places and times you'd rather not.

 

[Zorrick]

I must be mistaken about the shift bellows then.

I did previously removed the lower casing and ensure it was in forward gear when reassembling, although if you can see from the photo, when in full forward gear, it is almost at the 11:55 position instead of straight forward at noon. When in reverse it seems to get to around the 2pm position (instead of say 3?)

I have no problem doing the other additional maintenance, but with a tight schedule and limited season I'd like to prioritize the essentials first, if I can get it working with only a cable replacement then I'll be happy.

Rick Stephens If I do as you suggest and pull the full drive off (as opposed to just the lower) is there going to be any sort of additional testing I can do to determine the cause? I have certainly made sure it was in gear when reassembling previously, I've done it about 3 times in the last month now.

Just trying to get some more ideas for when I get a chance to go back to look at it, thanks for the input everyone.

 

[Rick Stephens]

If the brass shift shoe on the DRIVE is in forward and stops turning when it faces the bow of the boat, then the drive is right.

If in forward, the upper shift shaft with the U shaped channel that the brass shoe fits into isn't facing perfectly fore and aft, then your shift cable, linkage and/or adjustments have a problem.


Need to pick which based on the way things are in front of you.. I don't get accurately enough from your posts which is the problem.

 

[Zorrick]

Thank you for the feedback everyone.

Took off the entire drive as per Rick's suggestion, it was a good idea for sure, I found that the previous owner had put a bad gasket on which was causing a leak in the shift area. There was about 3 tablespoons of weird white corrosion - All around the shift cable! There was no way it was getting full range of movement.

Everything was going back together nicely and looking good - when I started torquing down the last bolts, it turns out I had the intermediate shift shaft mis-aligned and I bent it.

Tried to heat and bent it back but it cracked, so now i'm waiting for parts for next week.

Hopefully this will solve the issue. Will update when I can!