Bukh dv36 very stiff gearshift lever

[Graham Harvey]

box

[Jen-in-Wellies]

Welcome to the forum. 

First question. Is the stiffness in the gear change felt at a control lever? 

Second question. Have you tried disconnecting the gear cable from the lever at the box? If so, is the lever at the gearbox stiff to move? 

The more information you give, the fewer answers we need to tease out and the quicker your problem is solved. 

[Graham Harvey]

The gearshift lever on my ZF gearbox is very stiff. Particularly trying to find neutral is difficult without going through it into either forward or reverse. The problem is not the morse cable as I  tested the box with it detached. I  wonder if there is any form of adjustment possible with the mechanism?

[Tracy D'arth]

4 minutes ago, Graham Harvey said:

box

I think there should be more to this post?

 

What gearbox is fitted? Bukh don't make there own.

[Jen-in-Wellies]

I've merged the two topics. The second one contains more information, including gearbox make and that it is within the box, not the teleflex cable/lever.

Jen

[Graham Harvey]

The gearbox on this Bukh dv 36 is a ZF BW 7 model. I think that it the type most commonly fitted to this engine & the DV 48. It has oil up to the diostick level.

[Mad Harold]

24 minutes ago, Graham Harvey said:

The gearbox on this Bukh dv 36 is a ZF BW 7 model. I think that it the type most commonly fitted to this engine & the DV 48. It has oil up to the diostick level.

Is it a Hurth gearbox?

If so, when the gear cable broke on mine,because I was out in the sticks, I had to move the deck plates and change gear with a brush handle with a nail in the end.

The gearbox didn't have any stops on the gearchange itself but relied on the morse control to position the arm correctly.

The result with the brush handle was that you could go from forward to reverse through neutral very quickly and it took quite a bit of practice to develop a light enough touch to find neutral and reverse.Forward was easy as that was a straight push down, but finding neutral without bashing into reverse was tricky.

The oil in the Hurth gearbox is ATF by the way.

[Tony Brooks]

19 minutes ago, Mad Harold said:

Is it a Hurth gearbox?

If so, when the gear cable broke on mine,because I was out in the sticks, I had to move the deck plates and change gear with a brush handle with a nail in the end.

The gearbox didn't have any stops on the gearchange itself but relied on the morse control to position the arm correctly.

The result with the brush handle was that you could go from forward to reverse through neutral very quickly and it took quite a bit of practice to develop a light enough touch to find neutral and reverse.Forward was easy as that was a straight push down, but finding neutral without bashing into reverse was tricky.

The oil in the Hurth gearbox is ATF by the way.

 

No, mine was a ZF design made by a Spanish Company that I could never remember or pronounce. It is a mechanical box.

 

I never had any trouble with mine, but this sounds more like a bent or stiff cable than a gearbox fault. I suspect the gearbox lever has a detent that would make it stiff to get the initial movement by hand.

 

Regrettably, my DV36 manual with the gearbox section went with the boat, but I don't recall any adjustments.

 

Contact TW Marine, who are the inland specialists for these engines.

[Graham Harvey]

I have spoken to TW Marine who are, as you say, most knowledgeable & helpful. I have received some advice which I  shall act on shortly. 

The gearshift movement is very stiff both forwards & backwards with a further problem of not being able to find neutral easily. Having detached the Morse cable from the arm on top of the gearbox, it is possible to shift gear by hand but against considerable resistance. 

The advice I have received is as follows:

If the fitting containing the gearshift arm was taken off for some reason it might  have been replaced without the appropriately thick gasket. When re-fitted this might cause the mechanism to be located too tightly, that is, to cause it to bind on the adjacent surface? This seems to be distinctly possible to me. I shall investigate.

[Tony Brooks]

Thanks for that information, it may well help others.

[Stilllearning]

13 hours ago, Graham Harvey said:

I have spoken to TW Marine who are, as you say, most knowledgeable & helpful. I have received some advice which I  shall act on shortly. 

The gearshift movement is very stiff both forwards & backwards with a further problem of not being able to find neutral easily. Having detached the Morse cable from the arm on top of the gearbox, it is possible to shift gear by hand but against considerable resistance. 

The advice I have received is as follows:

If the fitting containing the gearshift arm was taken off for some reason it might  have been replaced without the appropriately thick gasket. When re-fitted this might cause the mechanism to be located too tightly, that is, to cause it to bind on the adjacent surface? This seems to be distinctly possible to me. I shall investigate.

Is it possible, with good lighting and access, to be able to see if there is a gasket fitted? Thick fibre/felt gaskets are often quite easy to see, and the lever mechanism could be visibly held slightly away from the gearbox body.

[Graham Harvey]

I have now taken off the unit containing the gearchange lever & confirmed that it is working smoothly with three 'detent' positions. There are no signs of the moving part of the mechanism binding or rubbing on any surface due to insufficient clearance related to the gasket thickness. It seems that the stiffness is due to some resistance of the gearbox internal (sliding) parts? I fear that I  am lumbered with a stiff, imprecise gear shift or else remove, strip & have the gearbox overhauled. 

[Tony Brooks]

It one of the cables is maladjusted or if a cable is bent through too tight a radius or worn, then you will get smooth operation with nothing connected to the cables by stiff when connected. Before even thinking about getting the gearbox overhauled, please ensure all beds in the cables are as large as possible.  Then disconnect both cables from the engine end:

 

Set the control lever to neutral and hold the throttle lever on the engine in the idle position. The cable fitment should just drop into the lever, if not, adjust the position of the fitment on the cable end so it does.

 

Next, set the control lever to slow ahead or astern, which does not matter. Do not do this step with the lever in neutral. Ensure the gearbox lever is in neutral and the trunnion o the cable should just drop into the hole in the gearbox lever. If not adjust the trunnion on the cable so it does.

 

Have you lubricated the innards of the control lever? Especially the trunnions that join the cables to the levers.

 

Also remember that this is a mechanical box, so you are sliding metal parts inside the box, this needs more force that just twisting the control valve on a hydraulic box.

 

[Graham Harvey]

Thanks for the advice Tony. I will check the cable operation as you describe next time I'm on the boat.

[Tony Brooks]

8 hours ago, Graham Harvey said:

Thanks for the advice Tony. I will check the cable operation as you describe next time I'm on the boat.

 

Sorry, wrote the instructions back to front - I blame my age.

 

First do the gear cable with the lever and gearbox in the neutral position.

Then do the throttle cable with the lever in slow ahead or astern and the injection plump lever in idle.

 

The reason is that may controls have a spring-loaded throttle cable anchor in the control that moves as you go between neutral and in gear to prevent the engine revving before the box is in gear.

 

Once again sorry to mislead.