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  1. #1
    Join Date
    May 2010
    Location
    Ireland
    Posts
    37

    Default Hurth HBW50-3R Gearbox problem

    Towards the end of the season I had some problems with the gearbox. The engine is running well but there seemed to be no drive when the revs go up. The propellor is turning but it seems that only a fraction of the usual power is actually being delivered at the prop. Not sure the age of the gearbox but definitely more than 20years!

    I did some experiments one evening while it was very calm. Turned the boat around on the mooring so she was moored by the stern and tried going ahead. Not much push. Disconnected the gear cable from the lever on the gearbox and put it into forward - much more drive. So maybe the lever wasn't being thrown far enough. I adjusted the cable position on the throttle/gear selector so it should travel further and on the gearbox level so that for a given travel it should rotate through more angle.(See diagram). This seemed to work. I cast off and motored around the moorings at 5 knots and did some backing up and going forward etc. Not sure if this is a proper long term fix or does it just postpone things. However on the day we craned out I thought again that there seemed to be less than full thrust.

    Is this a known type of failure mode for these gearboxes?

    image.png

  2. #2
    Join Date
    Aug 2004
    Location
    Cumbria; U.K.
    Posts
    2,970

    Default Re: Hurth HBW50-3R Gearbox problem

    Could well be wear, either in the shifting device itself, which moves the central clutch cone or the cones themselves. Your fix might buy a little time, but I'd get it repaired, which means dismantling the 'box.
    The shifter component shouldn't be too expensive, (I'd hope!)
    When I had need of a Hurth repair, I found canal boat yards were good.

  3. #3
    Join Date
    May 2009
    Location
    Wirral
    Posts
    366

    Default Re: Hurth HBW50-3R Gearbox problem

    When did you last change the gearbox oil?
    Leisure Owners Association

  4. #4
    Join Date
    May 2010
    Location
    Ireland
    Posts
    37

    Default Re: Hurth HBW50-3R Gearbox problem

    Hi, thanks for the replies. Gear box oil was last changed 3 seasons ago when I got the engine serviced professionally. Most years I’ve just done the engine oil and filters and changed the coolant. I haven’t checked the oil level yet, I suppose that I should have started there.

  5. #5
    Join Date
    Jul 2012
    Location
    Gran Tarajal
    Posts
    52

    Default Re: Hurth HBW50-3R Gearbox problem

    sounds like your clutch is slipping, i had similar and fitted new discs

  6. #6
    Join Date
    Jul 2016
    Posts
    142

    Default Re: Hurth HBW50-3R Gearbox problem

    I have the same gearbox and a similar problem. My gearbox is ok in forward gear but slips in reverse three times out of four which makes mooring / lock manoeuvres a bit exciting!!!

    I would initially change the oil (ATF fluid) and revisit the cable shift to ensure that lever has full throw. That did not work for me.

    My prop shaft turns in reverse but when I tested the rpm using a laser device bought cheaply on eBay it was only turning at about 280rpm. Conclusion was slipping clutch.

    Options for me were:
    1) Proffesional gearbox rebuild £300 to £500 plus removal/refit. I was not confident that my mechanical skills were up to doing the job myself.
    2) Replace gearbox with new. No longer produced but compatible alternatives available from PRM and others - c.£500 to £700 plus removal/refit and need to shorten prop shaft by about 25mm
    3) Buy 2nd hand

    It took 2 months to find one (that I was confident was working ok and a low use/newish model) but I eventually bought a second hand unit for £75 and will fit it next week hopefully. My new one was bought on eBay and came from a canal house boat following a prop upgrade by a new owner. Most units advertised had no or dubious provenance and were about £150. I did not want to buy one with faults obviously so waited for the right one(hopefully).

    PM me if anyone wants more info on option 1 or 2 above, I did a fair bit of research.
    Last edited by Dutch01527; Yesterday at 05:36.

  7. #7
    Join Date
    Jan 2013
    Posts
    222

    Default Re: Hurth HBW50-3R Gearbox problem

    Quote Originally Posted by Dutch01527 View Post
    I have the same gearbox and a similar problem. My gearbox is ok in forward gear but slips in reverse three times out of four which makes mooring / lock manoeuvres a bit exciting!!!

    I would initially change the oil (ATF fluid) and revisit the cable shift to ensure that lever has full throw. That did not work for me.

    My prop shaft turns in reverse but when I tested the rpm using a laser device bought cheaply on eBay it was only turning at about 280rpm. Conclusion was slipping clutch.

    Options for me were:
    1) Proffesional gearbox rebuild £300 to £500 plus removal/refit. I was not confident that my mechanical skills were up to doing the job myself.
    2) Replace gearbox with new. No longer produced but compatible alternatives available from PRM and others - c.£500 to £700 plus removal/refit and need to shorten prop shaft by about 25mm
    3) Buy 2nd hand

    It took 2 months to find one (that I was confident was working ok and a low use/newish model) but I eventually bought a second hand unit for £75 and will fit it next week hopefully. My new one was bought on eBay and came from a canal house boat following a prop upgrade by a new owner. Most units advertised had no or dubious provenance and were about £150. I did not want to buy one with faults obviously so waited for the right one(hopefully).

    PM me if anyone wants more info on option 1 or 2 above, I did a fair bit of research.
    My similar problems, turned out to be worn selector forks on the forward gear face.
    As I was investigating my lack of forward gear, between tides @ Castletownberehead, I reversed the selector which cured the problem.
    5 years later I junked engine and gearbox for a new unit. But, the problem never occured again in about 4000 hrs running.

  8. #8
    Join Date
    Jul 2016
    Posts
    142

    Default Re: Hurth HBW50-3R Gearbox problem

    Quote Originally Posted by Flica View Post
    My similar problems, turned out to be worn selector forks on the forward gear face.
    As I was investigating my lack of forward gear, between tides @ Castletownberehead, I reversed the selector which cured the problem.
    5 years later I junked engine and gearbox for a new unit. But, the problem never occured again in about 4000 hrs running.
    Interesting - by forward gear face do you mean the external gear selection lever on the gearbox?


    I have tried manually changing gear and problem persists.

  9. #9
    Join Date
    May 2009
    Location
    Wirral
    Posts
    366

    Default Re: Hurth HBW50-3R Gearbox problem

    I had the fault that it would go in to reverse ok but when put into forward the propeller would only turn slowly as if it was slipping in the gearbox.Didn't think it could be worn as engine nearly new when bought boat.
    Had this problem for a few years and find it I change the gearbox oil the problem virtually goes,so it it is if something is sticking inside the gearbox.
    Leisure Owners Association

  10. #10
    Join Date
    Jan 2013
    Posts
    222

    Default Re: Hurth HBW50-3R Gearbox problem

    Quote Originally Posted by Dutch01527 View Post
    Interesting - by forward gear face do you mean the external gear selection lever on the gearbox?


    I have tried manually changing gear and problem persists.
    No, I mean the gear selector forks on the sliding shaft inside the box. My box was not a Hurth box, and had twin cone-clutches, one for forward and one for reverse. Instead of cone-clutches (which are self energising) the Hurth uses multiple plate clutches.
    To get at it you have to dis-assemble the box.

    Look here http://www.wbryant.com/temp/hurth_manual.pdf

    @ 1.5 where it actually refers to the item,

    Good luck

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