Drive problem.

[Allan]

Not good news!

I now have a lot more information.
The joint, shaft and prop are all OK. The probem appears to be in the gearbox.
The gearbox is a Hurth HBW 150 made by ZF (model ZF15M). I have learnt that losing drive in one direction is normally caused by wear to the clutch plates, which then need replacing. The only thing that is not consistent with this is that normally the debris from this wear contaminates the fluid but my fluid, on the dipstick, appears to be clean.
I'll be on the boat tomorrow to drain the oil and see if there is contamination settled out in the bottom.
If anyone has any experience of this type of gearbox or problem, I would be interested to hear from them.
Allan

 

[Heckler]

I now have a lot more information.
The joint, shaft and prop are all OK. The probem appears to be in the gearbox.
The gearbox is a Hurth HBW 150 made by ZF (model ZF15M). I have learnt that losing drive in one direction is normally caused by wear to the clutch plates, which then need replacing. The only thing that is not consistent with this is that normally the debris from this wear contaminates the fluid but my fluid, on the dipstick, appears to be clean.
I'll be on the boat tomorrow to drain the oil and see if there is contamination in settled out in the bottom.
If anyone has any experience of this type of gearbox or problem, I would be interested to hear from them.
Allan

Just be aware that a badly fouled prop will not generate much drive, that the symptoms are similar to a slipping clutch. The reason is that if it is fouled and isnt driving then no power is being used, think prop on an aeroplane, they feather it to stop it turning a dead engine. It is the same effect.
Stu

 

[Allan]

Just be aware that a badly fouled prop will not generate much drive, that the symptoms are similar to a slipping clutch. The reason is that if it is fouled and isnt driving then no power is being used, think prop on an aeroplane, they feather it to stop it turning a dead engine. It is the same effect.
Stu

Many thanks for that, I really wish it was a fouled prop! We lifted the boat out of the water on Saturday.
Allan

 

[scottie]

See my earlier post hurth box is small mechanical with plates as described.
Box is light enough to remove yourself and simple to repair
Essential that you check control cable adjustment after refitting the box

 

[Allan]

Great service from Lancing Marine.

I have now stripped the gearbox yesterday and found one of the thrust washers is very worn. As I started writing this Miss Postie dropped the parts through my letterbox. I'm off to rebuild it and should have it back in later. Great service from Lancing Marine.
Allan