Hurth HBW50-3R Gearbox problem

[peteK]

Hi,

After talking to lots of people the advice I got was to replace the gearbox with a TMC40. The Hurth HBW50 stopped being made about 10 or 15 years ago and while various companies can supply new or reconditioned Hurth's they generally only recommend that where there is no space to fit the TMC40 which is about 4cm longer and has 5mm more offset between the input shaft and output shaft.

Having explored the darker recesses of the engine compartment I will also replace the engine mounts and the drive plate too. And add a RND flexible coupling. (Are any boat jobs ever limited in scope or do they always add more extra steps?)

Thanks for all the replies,

Conor

Did you ever try changing the gearbox oil?

 

[Brent Swain]

Good to hear they dropped the Hurth 50. Friends had all kinds of trouble with them . Some gave out in the first 60 hours.

Avoid like the plague, super soft Yanmar mounts .They have broken free , and left several engines rolling around in the bilges ,sinking one boat off the Great Barrier Reef.

 

[conor54]

@peteK - I wasn't able to do an experiment with changing the oil as the boat is out of the water for the winter. With my boat to change the gearbox I need to take the rudder off to move the shaft backwards to get clearance, so if that didn't solve it then I'd need to lift out again.

 

[Hydrozoan]

I think that my Hurth HBW50 has lasted 30+ years with a 20 hp engine. A bigger gearbox would undoubtedly be better but would need modifications to the prop shaft and engine mountings. I am happy to replace like for like and see how it goes.

I cannot (yet) claim that longevity, but mine has lasted 23 years with 18HP and is still going fine with annual ATF changes.

 

[peteK]

@peteK - I wasn't able to do an experiment with changing the oil as the boat is out of the water for the winter. With my boat to change the gearbox I need to take the rudder off to move the shaft backwards to get clearance, so if that didn't solve it then I'd need to lift out again.

5 people and a dealer recommended changing tho oil surprised you decided to change the gearbox.