Sanity check on Bukh DV20 gearbox shift

[Durcott]

Hi Folks, had a great sail this weekend, I hope most of you got to spend some time on the water.

Anyhoo - I have a 'new' boat with a Bukh DV20 from around 1984 ish.

The Morse gear was playing up while getting her ready, and I found a great deal of wear when I stripped it down. (It's on a Sadler 32 - a cast aluminium housing - I think the gears are aluminium, and the shaft carrying the gear selector cog is steel with a steel pin to engage with the selector gear.) The wear made it very hard to get the operating pin to stay engaged with the operating cog.

It finally failed to drive the gear selector on its first trip out, but luckily I had planned an alternative.

I'm happy with the idea that a 30 year old gear selection lever might get a bit worn, but I would like to sanity check just how much effort one would expect to need when manually operating the gear lever at the gearbox.

It doesn't feel excessive, but should it be 'silky smooth' or should it be 'industrial' in its action?

There is a fair amount of clunk as the gears engage, which worries me a little, as I thought the Bukh gearbox featured clutches. Perhaps these clutches are similar to the old Ford Cortina automatic? Errr - shall we say 'enthusiastic'?

Any thoughts would be appreciated.

Jeff

 

[Mistroma]

It was always fine on my old Southerly 95 with a DV20. I used to just nudge it into gear with my shin and out again with the back of my leg when berthing. It moved easily and movement was smooth when adjusting by hand. Different boat of course but I didn't consider it took much effort to engage forward or reverse. There was enough initial resistance to let you know it was going into gear. I have done it by accident when falling against the lever but certainly knew it had moved but didn't get anywhere even vaguely close to bruising my leg.

I don't remember any excessive sound either. The only problem I had was due to running into a submerged 40' square of Visqueen plastic. It melted on the shaft and stopped the engine. I re-started but it sounded like a load of ball bearings being mixed with a large gear wheel. Fortunately, the DV20 gearbox had a spring loaded gear wheel designed to disengage drive if shaft was stopped suddenly. Everything was fine once the Visqueen was cleared away as the system resets once the shaft is free to turn.

 

[James_Calvert]

Mine started off quite stiff when new then got really stiff after a few years, but since I took it apart and rebuilt it, with a bit of grease in the right places, it is quite light to the extent that it's quite easy to rev up or slow down by mistake if I knock the lever. Before the rebuild, the gear disengage knob (whatever it's called) also tended to seize up over the winter, but it has been no problem since.

IIRC there's a ball bearing with a spring inside the housing which is forced against the mechanism which provides the friction. If the ball can't move into the housing against the spring - because it's all clogged up - it can become very stiff to operate.

There is a lubrication point I think, but it's inside and almost impossible to locate whilst the mechanism is in place in the Sadler.

 

[SimonJ]

Hi Folks, had a great sail this weekend, I hope most of you got to spend some time on the water.

Anyhoo - I have a 'new' boat with a Bukh DV20 from around 1984 ish.

The Morse gear was playing up while getting her ready, and I found a great deal of wear when I stripped it down. (It's on a Sadler 32 - a cast aluminium housing - I think the gears are aluminium, and the shaft carrying the gear selector cog is steel with a steel pin to engage with the selector gear.) The wear made it very hard to get the operating pin to stay engaged with the operating cog.

It finally failed to drive the gear selector on its first trip out, but luckily I had planned an alternative.

I'm happy with the idea that a 30 year old gear selection lever might get a bit worn, but I would like to sanity check just how much effort one would expect to need when manually operating the gear lever at the gearbox.

It doesn't feel excessive, but should it be 'silky smooth' or should it be 'industrial' in its action?

There is a fair amount of clunk as the gears engage, which worries me a little, as I thought the Bukh gearbox featured clutches. Perhaps these clutches are similar to the old Ford Cortina automatic? Errr - shall we say 'enthusiastic'?

Any thoughts would be appreciated.

Jeff

Well, I have a 30 year old BUKH 20 as well. I have done major miles (motoring down to Portugal twice with light winds, up and down US/Canada east coast & then at tickover for much of an Atlantic trip from Antigua to Azores). I had concerns like you at various stages but invariably find it is the morse gear and control lever which sticks and ultimately gives up from time to time, as it inevitably does. I have changed both cable (easy) and gear/throttle control lever. Unfortunately if the latter is original & needs overhal spares are rarely available and a replacement has different dimensions which may or may not be a problem for you. I found a nearly new one on Ebay eventually from which i extracted parts. Replacement cables are universally available but you need to get the length right and choose the higher quality version.
Locally at my gearbox I can shift gears, just, but it is quite hard and there is always a slight clunk!
If you do a search on this site as I did when I had a problem you should come up with more useful info

 

[James_Calvert]

Re the clunk, my Sadler 32 has a folding prop, so I get worried if I don't hear it clunk into position!

I think my gearbox does tend to complain if there's no significant pause in neutral when manoevering, but I try to avoid that.

 

[chewi]

Hi Folks, had a great sail this weekend, I hope most of you got to spend some time on the water.

Anyhoo - I have a 'new' boat with a Bukh DV20 from around 1984 ish.

The Morse gear was playing up while getting her ready, and I found a great deal of wear when I stripped it down. (It's on a Sadler 32 - a cast aluminium housing - I think the gears are aluminium, and the shaft carrying the gear selector cog is steel with a steel pin to engage with the selector gear.) The wear made it very hard to get the operating pin to stay engaged with the operating cog.

It finally failed to drive the gear selector on its first trip out, but luckily I had planned an alternative.

I'm happy with the idea that a 30 year old gear selection lever might get a bit worn, but I would like to sanity check just how much effort one would expect to need when manually operating the gear lever at the gearbox.

It doesn't feel excessive, but should it be 'silky smooth' or should it be 'industrial' in its action?

There is a fair amount of clunk as the gears engage, which worries me a little, as I thought the Bukh gearbox featured clutches. Perhaps these clutches are similar to the old Ford Cortina automatic? Errr - shall we say 'enthusiastic'?

Any thoughts would be appreciated.

Jeff

I'd be tempted to watch the back of the morse while someone else operates the controls, especially for a new to you boat that may have been badly assembled.
If either the gear or throttle linkage is pinned to the wrong hole in the lever , the movement through neutral might be attempting to compress either cable, which will feel rough.
the same scenario applies at the gearbox and throttle end.

Note how they are pinned to the levers and move the lever without one or other cable disconnected to see if the roughness is removed.
Pinning either a hole closer to the pivot might alleviate that, but you'd then need to check it still gave enough throw to engage gear or rev up.