Bukh DV20 Gearbox Oil Leak Solved

[alegood]

Hello.

 

To all those who helped me a little while back in re-powering my boat - MANY THANKS !!

The Bukh DV20 is a many splendid thing and I would highly recommend it.

 

I did have a long running gearbox oil leak issue with it though and I thought I would share the following.

 

After every cruise I would find a puddle of oil underneath the gearbox which led me to believe that the gearbox input oil seal was failing. Sometimes it would leak a lot, other times hardly anything. Puzzled.

So I proceded to take the box off and replace the seal. For those who don't know this is accessed from INSIDE the box, so you need to undo the allan bolts and take the end plate off. I then dug out the old seal, which didn't actually appear to be to bad. I put the new one in, however I didn't have the right tool and so I struggled to get it in, as it is such a tight fit, and I was a little worried that I had damaged it. Nevertheless I put the gearbox back on and reconnected everything. The same thing was occurring, variable amounts of oil under the box. I concluded that either I had damaged the new seal, or that it wasn't in quite straight.

So I bought a new one and T W Marine kindly lent me their seal replacement tool (which worked a treat). I put the box back on, refilled it and started the engine. With the boat tied to the bank and in gear, perfect - hooray. I took the boat for a spin and then back to my mooring. I looked in the engine bay and there was oil under the box. I was beginning to suspect the output seal (although there was no sign of oil from it at all), which I hadn't changed, or as a worst case a cracked casing. I put the boat back in gear and, with it still tied to the bank, revved it quite hard. No leak. I put it in reverse and, again, revved it quite hard. GEARBOX DIPSTICK POPPING UP AND DOWN !!!!!!!!!!

So after all that hassle, the leak was caused by the two little 'O' rings on the dipstick filler being worn meaning that the dipstick is loose enough to pop out. But it only does it in reverse, I suppose when that shaft is engaged and spinning underneath it it must cause some sort of pressure.

 

I hope this is of some help to anyone, and that it saves them a lot of time and effort and money!!!!

 

Take care. Ollie

[luctor et emergo]

Thanks for that, I'll keep this in mind when I start using my Bukh 20.

[kendo]

Top tip. Thank you.

(Had the same problem).