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URGENT HELP PLEASE - Lister Blackstone Box Om HA2 Stuck In REverse.


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Can anybody help please?

One of our Blackstone boxes (mechanical on HA2) has just stuck in reverse, and it is now not possible to get it out.

We don't have any kind of workshop manual, but with lid off, there are no obvious failures we can see.  It is well lubricated, and all springs on the clutch (for ahead, I think) seem to be present.

I can't contact either vendor or local engineer.

Can anyone give any idea as to whether any self help might just be possible, please?

There were no nasty noises at the time, and it was not being stressed in any way.

Thanks

 

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Define "stuck in reverse". Do you mean that the lever won't move out of the reverse position, or that the gearbox still drives in reverse even when it's in neutral?

AFAIK no Lister-Blackstone box uses springs on the clutch. certainly mine doesn't. It's held in forward by over-centre leavers.

Possibly the linings on the reverse brake-band have broken up and jammed between the band and the drum. Can you see the reverse rocker? It looks like an oversize valve rocker-arm and is mounted on either the left or right, depending on the direction of rotation of the engine. One end is operated by a lever and roller on the gear-selection cross-shaft (the one with the external gear lever on it) and the other end has an adjustment screw with locknut bearing on a projection on the reverse brake-band. If that lever is immovable due to brake-band problems then that will stop the lever going over and jam the selection shaft in reverse. Temporary fix would be to slacken off the adjustment screw on the end of the rocker.

Cheers,

 

MP.

Cutaway drawing here: rgearbox1.jpg

 

 

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Sorry MP, for not replying sooner.  Have had a pig of a time since I posted for help.

To be clear it is that the operating lever becomes unmoveable, so you can't actually disengage reverse.

We now know that the two pairs of short links with pivots at each end that form part of the ahead mechanism seem to be throwing too far, such that when fully in the reverse position there is no angle between them and what they are meant to be pushing on, so they are not able to make the sideways movement they need to to actually move "forward"

You can free the box eventually with the lid off, by putting a pair of screwdrivers behind these links and "encouraging" them in the direction they need to move.  The problem is it will quickly do it again

What we can't work out is what has suddenly changed, as nothing inside the box looks detached or damaged.  We thought it was an issue with the end stop that limits the movement of the actuating lever in the reverse direction, but after making a lot of adjustment, it is still doing it.

I have been in contact with vendor of engine by phone, but he is many many miles away, and we have exhausted any suggestions of things I can do that I feel comfortable with.

We now hopefully have an engineer from a local yard coming to look at it within the next hour, but I am not confident he will find something quick and cheap that will fix it.  I hope I'm wrong!

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Both the fork which actuates the ahead gear and the lever-with-roller which actuates reverse are keyed onto the cross shaft with bolts. If either of those has come unscrewed. then either the fork or the level will have moved relative to the shaft, possibly producing the effect you're seeing. The threads are in the fork/lever, and the bolts have a plain section on the end distant from the head. They screw into the fork/lever and the plain end projects into a plain hole in the shaft.

 

If you can see, check that both these bolts are screwed fully home. There should be lock washes on them. If the lock washer is loose, even if the bolt is tight, then the bolt has unscrewed and the fork or lever rotated on the shaft. If that's the case, loosenthe bolt further until the fork/lever rotates freely, and then snug it up just enough that you can feel when the plain end in going into the hole as you rotate it relative to the shaft. The bolt should then screw right down onto the lock washer. This bolt also locates the fork/lever axially, so getting it in the right position involves possibly moving it along the shaft too.

 

When  I put mine back together, I did all that before installing the gear clusters, so the parts may not even accessible with the box together. I'm not offering to take the cover off mine to check.

Cheers,

MP.

 

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It's been a long and difficult day where just about everything that could go wrong has, short of a close family member dying. (OK a bit of an exaggeration, but the large pile of stinking dog vomit we have just cleraed from the boat has been in line with much of the day so far!....)

In desperation, because we have so much on, I have asked an engineer at a boatyard down here to take a look.

His view is that there is far too much end to end travel on the parts mounted on the shaft.  AS you engage forward, the gear that the reverse brake band clamps down onto the outside of is physically pushed forward 3 or 4 mm beyond the edge of the brake band.  He says a movement of "tens of thou" is expected, but several millimeters most certainly not.

I don't think we can fix this ourselves, and negotiations are now going on with the seller of the engine and box, (who is based a very long way from where the boat has decided to break down, but trying very hard to be helpful).

Thanks to those who have responded, but I'm out of my comfort zone, and will need those who know much more about this than I do.

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10 minutes ago, alan_fincher said:


His view is that there is far too much end to end travel on the parts mounted on the shaft.  AS you engage forward, the gear that the reverse brake band clamps down onto the outside of is physically pushed forward 3 or 4 mm beyond the edge of the brake band.  He says a movement of "tens of thou" is expected, but several millimeters most certainly not.
 

He's right that there shouldn't be much endfloat. This was the exact problem that caused me to have to rebuild my box. In my case the problem was severe wear in the bearing, due to misalignment of the reduction box and bearing carrier because the mountings were broken. A more likely cause would be that the locating ring for the bearing ( part 11 in the exploded diagram) is loose, allowing the outer race to move in the bearing carrier.  That would be a relatively easy fix, but still involve removing the reduction box for access.

 

I would however note that even with lots of endfloat, I didn't experience the problem you're seeing.

 

MP.

 

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47 minutes ago, MoominPapa said:

He's right that there shouldn't be much endfloat. This was the exact problem that caused me to have to rebuild my box. In my case the problem was severe wear in the bearing, due to misalignment of the reduction box and bearing carrier because the mountings were broken. A more likely cause would be that the locating ring for the bearing ( part 11 in the exploded diagram) is loose, allowing the outer race to move in the bearing carrier.  That would be a relatively easy fix, but still involve removing the reduction box for access.

 

I would however note that even with lots of endfloat, I didn't experience the problem you're seeing.

 

MP.

 

Thanks,

All noted, and all helpful.

 

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1 hour ago, alan_fincher said:

 (OK a bit of an exaggeration, but the large pile of stinking dog vomit we have just cleraed from the boat has been in line with much of the day so far!....)
 

Who vommed!? And why? *Off topic, also sorry for the shit day.

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5 minutes ago, Starcoaster said:

Who vommed!? And why? *Off topic, also sorry for the shit day.

Not witnessed, but almost certainly Odin.

It smelt so bad we think he must have decided to eat s**t on one of the parts of his walk when he was not being observed.  Highly unusual, but not entirely without some very rare previous precedent.

I have never smelt dog vommit that smelt like dog poo until now.

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Right now, so am I...

It does seem very un-Odin-like to eat something horrific, given that he is both generally good (I may not have mentioned this before, but whilst setting up for the wake, I forgot about the dogs and went upstairs for a pee... It was only when I was um, fully committed as it were, that I realised I had left two Labradors unsupervised with the buffet. They had touched nothing, as I suppose is self-evident by virtue of the fact that this is the first you are hearing of it... :D ) and also rarely out of sight of one of you.

 

Are you 100% sure it was shitty vomit and not vomity shit? By which I mean, is the method of expulsion definitely confirmed as a launch from the roof hatch and not the stern gland, because in my professional experience, some peculiar-looking blends can come out of the back end of a dog.

 

Edited by Starcoaster
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8 hours ago, Starcoaster said:

Are you 100% sure it was shitty vomit and not vomity shit? By which I mean, is the method of expulsion definitely confirmed as a launch from the roof hatch and not the stern gland, because in my professional experience, some peculiar-looking blends can come out of the back end of a dog.

With extreme apologies to anybody still reading this.

Unless the dog was able to pass through them in lightening time large amounts of Royal Canin breed specific dry mix kibble, identical to what they had eaten only a short while earlier, then I'm convinced it came out the same end as it went in, (even though it didn't smell that way).  WE think he ate something nasty on a walk before being fed proper food, then his stomach didn't think that a good idea!

Odin wouldn't dream of helping himself to any food without permission.  We have on occasions left him in the kitchen with his bowl filled, and forgotten to give the "go on" command.  When we wander back in half an hour later he will be sat there surrounded by drool, but the food is untouched.

However if not supervised on a walk, they do both seem to tink that a bit of something most unsavoury is a good snack.

A bit like if you carry fresh water and a clean bowl they are not interested, but a disgusting muddy puddle is the best drink ever!

(Nothing else bad has happened overnight!)

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On 23/05/2017 at 09:41, mross said:

I suggest you don't use the gearbox until this is sorted as it is quite likely to suddenly self-destruct.  If you get it overhauled now you could save a fortune.

 

True, but it is jammed in astern and I doubt Alan is likely to attempt a cruise back to his home mooring backwards. 

If only he had a second boat on site he could use to breast them up as a pair for the trip:) 

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Hi alan.as i said when we spoke on the phone, check the nut on the end of the reduction box first then failing that make sure bearings have not broken up,reduction box side then if all fails remove cluster and check shaft nut,its a rectangular nut with a machine screw locking it into place.make sure that has not come loose.good luck

Edited by Orpheus 68A
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38 minutes ago, Mike the Boilerman said:

True, but it is jammed in astern and I doubt Alan is likely to attempt a cruise back to his home mooring backwards.

MtB, the OP said, "You can free the box eventually with the lid off, by putting a pair of screwdrivers behind these links and "encouraging" them in the direction they need to move.  The problem is it will quickly do it again"  I'm worried that something falls off and causes more damage.

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On 23/05/2017 at 10:33, mross said:

MtB, the OP said, "You can free the box eventually with the lid off, by putting a pair of screwdrivers behind these links and "encouraging" them in the direction they need to move.  The problem is it will quickly do it again"  I'm worried that something falls off and causes more damage.

 

Cornblimey, Is everybody expected to read the whole thread now before jumping in with uninformed comment??

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6 hours ago, Orpheus 68A said:

Hi alan.as i said when we spoke on the phone, check the nut on the end of the reduction box first then failing that make sure bearings have not broken up,reduction box side then if all fails remove cluster and check shaft nut,its a rectangular nut with a machine screw locking it into place.make sure that has not come loose.good luck

We checked the easy one, i.e, that on reduction gear.  Castellated nut secure, with split pin in place.

Boat is now left in marina, and I'm in negotiation with both vendor and the engineers at the marina, all of whom seem flexible about best way forward.

It means cancellation of some plans, but I was convinced it was not sensible or safe to carry on.

Going 60 miles up the GU with two 3 foot draughted boats breasted together would not have been a realistic prospect, and the boat is too far down at the front to pull on cross straps.

I have appointments elsewhere today, I am now on a train on my way to London), but am grateful to all who have offered advice and support.  Also to the marvelous RogerAllsop, who gave me an unexpected free ride from Croxley to Berkhamsted, thus making a difficult day much less stressful.  There are good people on the cut.

 

 

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