Alpha drive fault

[betty boop]

10 years or so of engineer free boating and Im finally going to have to concede to a marine engineer, one last hope on a forum post just in case

4.2 MPI into an Alpha Gen 2 - new matched Ali prop.

all was OK with new boat used for 4days then I had a ding on the prop (hitting an under water steel frame) in gear whilst mooring.

new prop sorted any issues then 6 weeks later she refuses to go into F or R gear whilst mid river entering a lock. only slamming the shift hard forced it into gear.

following Ian's You tube video I adjusted the shift mech, all cables are within movement/slack spec and shift adjusted correctly.

out of water all is OK with forward or reverse gear change.

fast forward 2 weeks and a long drive south upon launch she refuses to go into gear again - again hard slam on the shift stick forces a clunk into gear and an engine cut out.

Shift mech the readjusted in water, on the pontoon and shift is OK as it should be and used for 4 days in Torbay.

drive home FF another 2 weeks later on another launch and again she refuses to go into gear again - again hard slam on the shift stick forces a clunk into gear and an engine cut out.

Im stumped now - if all the cables are OK and the drive allegedly adjusted correctly then I fail to see why after towing something happens in the drive to prevent smooth gear selection. The only thing we can think of is the drive being warmed up after 2 hours river use the gear shift eased up and went perfect nice, quite & smooth for mooring but my understanding of the drive is it wouldnt warm up and any gear fluid would not be 'pumped' around the drive either & so far no fluid lost and no reason to suspect any leaks etc.

worth a post to see if theres any suggestion

[mlines]

Continually having to adjust the cable to get gear selection can be a symptom of the cable being stretched

[Ianfs]

That's exactly what I was thinking after reading your post Ian.

If you have made all the adjustments and it continues to play up its either a stretched cable or possibly a damaged end.

[betty boop]

wouldnt a stretched cable show up under the tolerance being out of the set limits unless it was acting like a bungee cable? Both the shift cable and selector cable operate freely with the required xxmm max limits (whatever it is ) when disconnected from the shift mechanism as per the instructions.

I even tried to select gear from the engine bay using just the gear shift cable end with engine running and it freely selected F or R gear. I understand what you're saying about the cable being stretched or even kinked and it would explain the resistance (stiffness) when moving the gear stick but not the happens one time and not the next. damaged end sounds feasible, with bouncing around on a trailer may be it works itself free?

the other problem I have aligning symptom and cause is the sudden start of the problem, literally over night

The history of the drive is it was removed in 2015, had the bellows/gimble bearing replaced as part of the Merc recommended scheduled /procedure I assume the shift cable was replaced under that same schedule as it recommended by Merc.

[Ianfs]

Hi Ian

When you tow, you will raise the drive into to towing position thus pulling on all 3 bellows including the shift cable bellows. This could possibly take it out of adjustment as indicated by you making a little adjustment then it worked then another tow and its out again.

There is another possibility that the mechanism in the leg got damaged when you stuffed the prop, but not as likely.

I'll take a quick look at the manual later but I still think it might be the cable. I've got a marine engineer coming tomorrow so I'll run it past him too.

[betty boop]

Hi Ian

When you tow, you will raise the drive into to towing position thus pulling on all 3 bellows including the shift cable bellows. This could possibly take it out of adjustment as indicated by you making a little adjustment then it worked then another tow and its out again.

There is another possibility that the mechanism in the leg got damaged when you stuffed the prop, but not as likely.

I'll take a quick look at the manual later but I still think it might be the cable. I've got a marine engineer coming tomorrow so I'll run it past him too.

cheers Ian - of course the raising of the drive - I didnt think about - (oh I feel so stupid cant see the woods for the tress ) so of course if Im lifting it may be bending pulling on the cable, any thoughts he has will be appreciated,

I need to remove the drive over winter as shes covered in anti foul and some barnicles that I want cleaned off and the skeg is corroded/pitted too and needs some TLC, it'll be a good time to replace the cable by the sounds of it.

[Dave]

Absolutely agree with Ianfs about the tilting for towing home stretching the cables...normally this would be ok, so you could have cables that are a touch short...just enough to pull too hard on them when lifted right up....just a thought.

[betty boop]

Absolutely agree with Ianfs about the tilting for towing home stretching the cables...normally this would be ok, so you could have cables that are a touch short...just enough to pull too hard on them when lifted right up....just a thought.

yes agree with that, by chance I put the drive into gear whilst in the trailer position and the throttle was solid no movement at all until I put it in neutral. On the last boat I was easily able to select forward/reverse whilst in the full raised position. Do the shift cables come in various lengths? if not it's suggested the routing could be suspect