Can't engage forward gear - WE'RE STUCK!!!!!!

demonboy

demonboy

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Can\'t engage forward gear - WE\'RE STUCK!!!!!!

We have an ongoing problem with engaging forward gear and our boat yard cannot sort it out. We have spent hundreds of euros getting the gear box stripped down, the clutch plate rebuilt, and so on, but the problem keeps re-occurring.

In a nutshell: when pushing the gear lever into forwards, nothing happens. There is no satisfactory 'clunk' which we get when putting into reverse. After 10 minutes or so of constantly trying this it occasionally engages. After motoring for half an hour or so, the gear appears to engage and disengage fairly satisfactorily. This morning, however, no matter how many times I put the lever into the forward position, nothing happened.

Two years ago the clutch plate was rebuilt as the first cause of the problem offered was that the plate was slipping. Fair enough.....after a repair job the problem appeared to go away for a while. Since then the problem started again and so we have had the gear box stripped and serviced. Twice. The mechanics SWEAR there is nothing wrong with the gear box and indeed claim it is in very good condition. They demonstrated this by manually engaging the clutch lever (the one on the side of the gear box) into both forward and reverse with satisfactory clunks in both directions.

So, because the clutch plate has been repaired and because the gear box is seemingly in good order we were then told that the gear lever on the binnacle was wearing out and was not moving the morse cable far enough. A couple of sprays of WD40 later we were told that before starting the engine we spend 10 minutes moving the gear lever forwards and backwards to ensure that any salt or dirt trapped in the gear lever teeth would be freed up. This dirt, we were told, was the cause of the problem. Well, if this is the problem this isn't exactly a practical work-around. We were told we would eventually have to replace the gear lever. However we have thoroughly investigated the point at which the clutch lever engages and disengages and there is absolutely nothing wrong with the cable. The cable pulls the clutch lever arm far enough back to engage forwards gear.

I appreciate this is a problem that can't really be solved without someone taking a look at this in situ, but I would be interested to know if (a) this sounds familiar to anyone and (b) if there are any simple checks I could do to help me tick off possible causes. It's driving Liz and myself mad!

It's a Perkins Prima M60 engine and Hurth gearbox dating back to 1989.
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

[ QUOTE ]
Twice. The mechanics SWEAR there is nothing wrong with the gear box and indeed claim it is in very good condition. They demonstrated this by manually engaging the clutch lever (the one on the side of the gear box) into both forward and reverse with satisfactory clunks in both directions.


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There but for the grace of God I guess.

If you are securely tied up alongside, can you engage the clutch lever on the side of the gear box with the engine running - i.e. someone at the gearbox, rather than using the morse and cables?

If you can, this would eliminate the gearbox and tell you that it is something between the morse lever and the clutch lever on the gearbox.

One other thought - could the clutch lever be kind of out of line, or loose, such that the cables pull, or push it, but it doesnt engage - I cant explain that any better, so hope you get the gist.
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

well, stating the obvious really..... but try engaging gear using just the lever on the gearbox- if that works every time, it's clearly the cable adjustment or a control head issue. If not, well, rather plainly a gearbox one.

Start from scratch - forget everything you've been told is perfect, and determine if it works without the control head & cable being used.
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

Does the gearbox always engage properly when manually moved at the gearbox itself.

If yes the problem must be in the cable or the selector.

Using WD40 to free off a cable is a time honoured and incomplete procedure. The WD40 will free the old grease for a while, but this is only an interim stage as the WD40 will have removed the lubricant and will then itself dry out fairly quickly so needs to be replaced with a longer term lubricant - zx1 is a great solution for this.

I would also be suspicious that the cable was in the correct position on the lever. If your lever is like mine, it will have a number of different positions to fit the end of the outer cable. These different positions are designed to change the amount of cable moved by the gaerbox cable at each selection of gear. - get the position wrong, and the gears will not engage every time, especially when cold.

I am sure you have probably already looked at all these, but it is the only thing I can think of.
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

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can you engage the clutch lever on the side of the gear box with the engine running - i.e. someone at the gearbox, rather than using the morse and cables?

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and

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well, stating the obvious really..... but try engaging gear using just the lever on the gearbox- if that works every time

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and

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Does the gearbox always engage properly when manually moved at the gearbox itself.

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My apologies, I probably didn't make that very clear. When the mechanics first reinstalled the gear box they did exactly as you all describe and, sure enough, it worked ok. However over the space of a few weeks the problem has begun again.

So, this morning I tried what you describe above and, sure enough, I can no longer manually engage the gear when moving the clutch lever at the gear box itself. As you say, I did this to ensure that the gear box is ok but if I can no longer engage in this way then it HAS to be something to do with the gear box and not the cable.

I'm wondering if the repair job they did a couple of years ago on the clutch plate has worn away again, but I can't see it. The repair job has only seen one season's action and of course the mechanics would have picked up on it since they are the same ones who did the repair.
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

If you have access to Nigel Calders book 'Boatowners Mechanical and Electrical Manual' you'll see he has some things to say about Hurth boxes:
'Hurth clutches in particular are very sensitive to improper cable adjustment'
And:'Hurth boxes do not have a distinct click when a gear is engaged. however, the lever must move through a minimum arc of 30 degrees in either direction'
There are some exploded views of a gearbox and instructions on clutch adjustment and cable adjustment. If you don't have the book and can't get hold of one PM me and I'll be happy to scan and send the appropriate pages.
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

At this point I would be reaching for the cheque book and getting a replacement gearbox.
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

[ QUOTE ]
So, this morning I tried what you describe above and, sure enough, I can no longer manually engage the gear when moving the clutch lever at the gear box itself. As you say, I did this to ensure that the gear box is ok but if I can no longer engage in this way then it HAS to be something to do with the gear box and not the cable.

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Yes, assuming that you disconnected the cable when testing as above - otherwise the vable/control may well prevent you from moving the lever sufficiently to engage gear.
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

A couple of thoughts:

Does the cable move the lever OK?

Did you remove the cables when you were moving the lever manually?

Cheers

Richard
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

It's a Hurth and is probably the same age as the boat, 18 years. I don't know what model it is but it was made in West Germany, so it gives you some idea of how old it is!

Yes, I DID disconnect the cables when moving the lever at the gear box. I moved the lever through its entire arc, to no avail.

I have a copy of said manual...Liz is flicking through it now. Thank you for your kind offer of scanning it though.

How much is a new gear box? Do I want to spoil my Sunday afternoon with this knowledge?
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

Another little fact: sometimes when leaving the gear in forward and it not engaging, I leave it forward. After about 2 minutes the gear will engage. Could this possibly mean something, somewhere is being affected by the vibration of the engine/gearbox? If so, what?
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

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Sounds a bit like a sticky spline.

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Care to explain a bit further? If you are referring to the splined transmission I would have expected a half-decent mechanic to have picked up on this.
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

Yes sounds like a selector hub in the box is sticking against its spring loading and not sliding along the shaft to engauge with the gear cone or blocking ring.
This could be caused by the indent pins/balls having worn their seats oval and wanting to spring out, jamming the selector hub.
Not knowing what engine size it is, but reading what you say about the lever having to move rearward to select forward gear, I would reckon its a Hurth HBW50 box, now known as the ZF5 as ZF have bought over Hurth.
Are you absolutaly sure that the lever on box side is tight on its spindle and not turning or slipping on it.
If you look at the rear face (output end) of the box, you should see the end of a shaft to the left side of the output drive flange, check if this shaft turns when the engine is idling in gear or neutral, and is it loosing any oil there, even the smallest weep.
This is a idler thrust shaft, which is fitted as an intereference fit and if it turns it will wear the alloy casing and allow axial movement in the idler shaft which would make gear selection difficult or impossible.
This shaft is just starting to leak oil on my boat and box is going to have to come out this winter to sort it.
I have a parts drawing, and manual some where on CD for the HBW 50- 2R.
Cheers, C_W
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

Hey CW - you're blinding me with science here but I'm keen to understand more and, if this is the HBW50, to find a manual. I've taken a couple of shots of the gearbox, one from either side (plus a snap of the plate). One shows you the clutch lever with the cable taken off (you can just see it underneath). The other is a better one of the whole unit. Could you confirm that it is the model you suggest?

gear3.jpg


gear2.jpg


gear1.jpg
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

I am interested, do you sail with your gearbox engaged in reverse?

Is this a problem every time you want to engage forward, or is it ok when moving around under engine once you have successfully engaged forward for the first time?

rgs
Paul.
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

Hi demonboy.
Its not the HBW50 unless its an older model than mine, as my dipstick is right at the front of the casing close to bhe bell housing, but in the drawing that 2Tizwos has put on you will see the shaft I am talking about No 24.
These boxes are designed to be put in reverse gear when sailing or been towed to lock the shatf/prop.
 
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