Stiff gear change - cables, clutch, dual station changeover?

[LittleSister]

I’m having real difficulty getting between forward, neutral and reverse in my new (to me) boat. Makes for rather exciting marina manouevring, especially in this unfamiliar to me long keeler!

Obviously condition and adjustment of morse cables is the primary suspect, but I’m wondering whether there might also be a clutch issue, or some problem with the dual station changeover mechanism. Any comments/suggestions/advice welcome.

Set up is dual station single lever (i.e. combined throttle/gear) controls; Bukh DV36 with (I think) ZF BW7 gearbox; Variprop feathering/reversing prop. The boat has been unused for a couple of years, and, from what I can understand, very little used in the few years preceding.

I did not notice any difficulty operating the controls before launching. Once afloat and underway I initially had a little difficulty changing over the dual station control between stations, but that seemed to resolve itself. Wheelhouse engine revs control seemed a bit approximate, with engine revs settling only after a few moments – suspected knackered or misaligned morse cable control to the wheelhouse - but didn’t notice this problem with the cockpit control.

Once underway, it was very difficult (two handed job) to get into neutral, and difficult to do so without going over into reverse. Similarly difficult coming out of reverse. Also continued to drive forward on several occasions when in what seemed to be neutral.

In shifting between forward and reverse loud clunk each time from prop and/or gearbox. Variprop manual does emphasize letting engine drop back to tickover before attempting change between forward/reverse. Rev counter shows tickover as 1,000rpm, which is within manual spec of 900 – 1,000 rpm.

Unfortunately, time pressures precluded investigating the cable set up etc. before I left the boat, and I won’t be able to go again until next weekend, but I urgently need to get this sorted, so would like to be going back to it armed with a bit more understanding. What does the team think?

 

[scottie]

Adjustment adjustment adjustment

You have to set everything up in neutral and work from there depending on which DS units you have there may be holes for locking pins to help you .
Try and equal out any backlash and it's not rocket science just tedious and sometimes repetitive.
Check that the rod ends on the cables are not bent particularly at ends.
Tickover seems a little high but within spec

 

[prv]

The obvious step one is to disconnect the linkage at the gearbox and see whether the gearbox itself is stiff or if the stiffness is in the cables. Most likely the latter, but you did wonder about the clutch.

Pete

 

[Kelpie]

Just troubleshoot it methodically, starting from one end of the control chain.

I ignored a stiff morse control for a few months, assuming it was the lever itself, at which I would chuck a bit of oil from time to time. It turned out to be the ball joint on the gearbox linkage itself that has seized, so the end of the morse cable was having to do all the articulating. I found this out when it snapped- fortunately with the boat tied up alongside at the time.

 

[Topcat47]

Just troubleshoot it methodically, starting from one end of the control chain.

I ignored a stiff morse control for a few months, assuming it was the lever itself, at which I would chuck a bit of oil from time to time. It turned out to be the ball joint on the gearbox linkage itself that has seized, so the end of the morse cable was having to do all the articulating. I found this out when it snapped- fortunately with the boat tied up alongside at the time.

I think this is more likely than the cable. Particularly the current crop of low friction morse cables. Another alternative is the change shaft into the gearbox.

 

[ianat182]

If you do have a dual station throttle/gear changing setup there should be a way that one or the other becomes disconnected,allowing you to use the preferred position. This may be as simple as allowing the non operative Gear/throttle to have a button that can be pressed in so that only throttle movement is possible; moving to the other operating position may then enable selection and throttle functions to be used(in this instance the button will be protruding from the handle,indicating that this is the preferred option.)
It follows that the alternative selection of operating position would work in the same way.
I have only the one position on my boat but had gear/throttle problems,now cured, after referring to the handbook and resetting the end clearances to the 4mm specified. One fault I did find was that the outer sleeve of the cable to the throttle has a section which has a groove that should be secured by a retainer on the the mechanism body, mine had jumped out of the retainer, so had lost the grip of the outer casing of the Morse type cable.
I ended up resetting the whole mechanism from scratch using the instructions. I t works OK now.
Just re-read your post, do you mean that you have a dual function rather than dual position setup?

ianat182

 

[LittleSister]

Thanks for all the advice. Keep it coming.:encouragement:

Adjustment adjustment adjustment

You have to set everything up in neutral and work from there depending on which DS units you have . . .

Check that the rod ends on the cables are not bent particularly at ends.
Tickover seems a little high but within spec

I don't have any manuals/handbooks for the controls or dual station changeover kit, so it'll be somewhat suck it and see. I'm guessing that each cable should have slight, but not excessive, free play.

I had previously noticed that the engine end of the throttle cable was poorly aligned, but not appallingly so, and it's the gear changing that seems to be the problem.

I'll rummage through the engine manual to see how easy it is to adjust the tickover.

The obvious step one is to disconnect the linkage at the gearbox and see whether the gearbox itself is stiff or if the stiffness is in the cables. Most likely the latter, but you did wonder about the clutch.
Pete

Yes, that's high on the agenda. I am suspicious of the clutch because I hadn't noticed any problem shifting the levers when it wasn't under load, and it seems just what you'd get if the clutch wasn't disengaging. Trouble is I know about clutches on 1950s/60s motorbikes, but don't understand how a boat gearbox clutch operates or whether it's operation can be adjusted. More research and/or advice required.

Just troubleshoot it methodically, starting from one end of the control chain.

. . . It turned out to be the ball joint on the gearbox linkage itself that has seized,

Methodical check through is the plan.

I'll now check out that linkage especially.

I think this is more likely than the cable. Particularly the current crop of low friction morse cables. Another alternative is the change shaft into the gearbox.

Not sure how 'current' the cables on the boat are - some could be 38 years old! I think the boat originally had just wheelhouse control, and the cockpit control and dual station changeover kit has been added relatively recently (with the accent on the relatively!).

If you do have a dual station throttle/gear changing setup there should be a way that one or the other becomes disconnected,allowing you to use the preferred position. . .
I ended up resetting the whole mechanism from scratch using the instructions. I t works OK now.

ianat182

The switch from one station to the other is by pulling and turning a lever (separate from the controls themselves). I don't have any instructions for the kit, which I think is this Teleflex kit http://www.tnorrismarine.co.uk/wp-content/uploads/2016/12/Dual-station-01.17.pdf but will keep searching.