Hurth Gearbox issue

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mollyoxford

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Can't find any ID on the gearbox - is either a Hurth 50, 100 or 150 - we have only got the installation instructions, no manual - but I am going to try tracking that down. Manual planetary anyway, hooked to a normal push-pull controller.

We seem to have not much 'GO' in astern all of a sudden. Ahead is just fine. Cables seem fine, engine revs fully in astern when disengaged, doesn't rev out when put in gear - occasionally stalls. Transmission fluid looked a bit yick so was changed and a slight cable tweak got us a tad more oopmh.

Think it could be the brake band needing adjusted (tightened)? Or a clutch on the way out (blackish ATF doesn't seem like a good sign to me...).
 
I had the same problem IIRC on a Hurth fitted to 40hp Volvo saildrive.

Problem was clutch and Volvo agent persuaded me to go for recon box not just do clutch cones.
 
The Hurth HBW50 etc series are basically similar, there is no brake band to adjust AFAIK. There should be an identifying label, it is sometimes spray-painted over by the engine manufacturer. If, as your post appears to say, there is enough internal friction in the box to sometimes stall the engine when in astern, together with black ATF, then, IMHO, your box seema to have a potentially serious problem. It might be a bearing breaking up. If it were mine, I would look at it ASAP. Delay could make for an even bigger repair bill, or total failure whilst at sea.
 
no brake band? I really need a manual now, I thought I knew how these things worked, clearly I have more to learn (like how it works in astern).

Fluid has been changed so I'll have another look at it.

There is no plate on the top or sides of the box at all,not even painted over. It may be on an inaccessible side/bottom as it is mounted on the boat. the bit that says 'Hurth, West Germany' is on the portside face of the box.

Be me and the boyfriend fixing the thing, so bill not so much of a problem Premature haulout more of a nuisance - but that's the case whether we fix it of get a new/reconditioned one. Guess we had better keep practicing the sailing manouveres...
 
Yes, you really need a manual, if you replace components, then adjustment shims etc. need to be set up. If it's like my HBW50 on a Beta engine, then it's an engine-out job to split the gearbox from the engine.
 
Thankfully, it doesn't *look* like an engine out (which would be some what annoying since it only just went back *in* before we bought her in March). The gearbox is, perhaps, the only really easily accessible part of the engine.
 
These gearbox's have a thrust bearing which when worn will allow too much movement to the internals,which is basically two motorcycle type cluch's.
I would not advise leaving it as it will fail! been there got the T shirt
Have it rebuilt/replaced now and don't become a casualty, you can normaly remove these gearbox's without removing the engine.
 
OK, bike clutches I can do :-) Used to be able to overhaul/replace one in about 20 minutes (that was over 10 years ago though...). Seriously need a manual now.

It's STILL a boat-out-of-the-water job :-( :-( :-( .

Which means also doing the other jobs lined up for that. Replacing seacocks for the kind with grease nipples, changing stern gland packing to the greaseless type, spraying topsides, redoing antifoul -hmph might as well do the rigging and replace the chainplates...

lol at the sig. "it's Heaven and Hell...." - could be about boat ownership :-)
 
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