Can't engage reverse gear

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gavin400

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Engine is Volvo MD1 with a Morse MTB1 dual lever control (one lever for throttle, one lever for gears)

It was becoming increasingly more difficult to engage reverse, until it got to the stage where it became impossible

So we installed new control cables

With the new cable disconnected from the gear mechanism on the engine, the cable operates smoothly and effortlessly throughout the full range of travel, forward, neutral, reverse (as did the old cable)

Similarly, the engine gear mechanism can be moved forward, neutral, reverse - reverse takes a bit of effort, although that may just be down to awkward access for my hand in the engine bay restricting my ability to give it a shove

When the cable is connected to the engine gear mechanism, we get forward and neutral but reverse is impossible to engage no matter how much force is applied

Both the cable and the gear mechanism have uninterrupted movement and the system has been operating this way for many years

Has anyone any thoughts?

Many thanks

Gavin
 
Can you engage reverse by pushing directly on the gearbox link arm (perhaps using a bar of some kind if access is difficult) whilst the engine is ticking over?

I would test with the engine running as sometimes gearboxes can be sticky if the engine is not turning.

If reverse engages properly and the cable movement when disconnected is smooth then surely it must the effective cable length which has slipped out of adjustment and you need to alter the cable end clamp position or whatever adjustment method is used on your system. There is often a "coarse" adjustment method such as alternative holes in the lever arm or a cable outer clamp, and "fine" adjustment such as a threaded bar.

Richard
 
Just some thoughts from me. I'm assuming we want a simple cheap answer before the gearbox is removed and dismantled. I'm no expert and am just trying to remember how my selector mechanism and control lever work.

If the cable pushes the lever into reverse and pulls it into forward, there will probably be less force available pushing than pulling. This could be compounded by a stiff reverse gear selection.

You seem to know what you are doing but have you got the cable fitted onto the control lever in the correct place? When I renewed my Morse control lever there were a number of options for fitting the cable depending on the engine/gearbox configuration. My lever is designed for universal use.

Is the outer casing of the cable secured adequately at both ends? If it was sliding that would affect gear selection.

When selecting forward/neutral/reverse is there the same amount of movement in the cable between forward and neutral as there is between neutral and reverse? Is the gear selector lever properly centred? Is there any play in it?
 
The fault was there so you changed the cables with no improvement therefor it is more likely the fault is in the box

They have cone clutches that wear and form horizontal grooves which lock the box up at times usually when hot and the tell tale is the large hammer kept to release the cones.

Time to open the box please Michael and spend the money if you can get the parts.
 
Could it be that the selector fork inside the gearbox is worn away, thus having insufficient travel to ensure that the cone engages astern?
 
I don't think it is the engine, as we have also replaced the engine - replaced the old Md1 with another MD1

The problem occurred with both engines.

There are a variety of holes on the gear selector lever for attaching the cable to, however it doesn't appear to make any difference what hole is used.

The cable outer sheath is secure and there is no sign of this moving during gear selection

Selecting reverse involves the cable pushing, rather than pulling, and this probably does require considerably more force
There is quite a lot of play in the selector lever and I'm now wondering if this is part of the problem as it seems to grind when attempting to select reverse
 
gavin400 said:
I don't think it is the engine, as we have also replaced the engine - replaced the old Md1 with another MD1

The problem occurred with both engines.

There are a variety of holes on the gear selector lever for attaching the cable to, however it doesn't appear to make any difference what hole is used.

The cable outer sheath is secure and there is no sign of this moving during gear selection

Selecting reverse involves the cable pushing, rather than pulling, and this probably does require considerably more force
There is quite a lot of play in the selector lever and I'm now wondering if this is part of the problem as it seems to grind when attempting to select reverse
Click to expand...

can you disconnect the gear cable then try to see what happens when you manually move the gear lever
 
http://boatinfo.no/lib/volvo/manuals/md1-d1-md2-d2.html#/32

Page 30 shows the gear box. Is this what you have? Can we assume your boat is in the water and the engine running when you are doing these tests?

You refer several times to being able to move the gear selector on the box by hand to the reverse position but you do not confirm that reverse gear is actually engaging.

You will see from the manual that the drive shaft actually moves forward and backwards when selecting gears and that the effect of the propeller rotating in water pulls the engaging cones to full engagement. Does your drive shaft move towards the shaft seal when you engage astern?
 
Bilgediver said:
http://boatinfo.no/lib/volvo/manuals/md1-d1-md2-d2.html#/32

Page 30 shows the gear box. Is this what you have? Can we assume your boat is in the water and the engine running when you are doing these tests?

You refer several times to being able to move the gear selector on the box by hand to the reverse position but you do not confirm that reverse gear is actually engaging.

You will see from the manual that the drive shaft actually moves forward and backwards when selecting gears and that the effect of the propeller rotating in water pulls the engaging cones to full engagement. Does your drive shaft move towards the shaft seal when you engage astern?
Click to expand...


I am carrying out the tests with the boat ashore, but when she was in the water the same problem was apparent

Yes, when engaging reverse by hand the shaft moves astern and reverse gear is fully engaging
 
Just a happy update

Having messed around with the gear selector mechanism, which took a full day due to the inaccessibility of the components and general hassle of all things connected to boat engines, I ordered and fitted a new gear selector cable and this solved the problem instantly.
Am not sure why the new cable solved the problem as the old one was only 2years old and appeared to be in excellent condition, however now up and running again
 
LadyInBed said:
"It was becoming increasingly more difficult to engage reverse, until it got to the stage where it became impossible

So we installed new control cables"

So you changed the cables again?
Click to expand...

Good point. I wonder if the OP's cable is taking too sharp a curve somewhere along its route and therefore shortening its useful life? The more expensive cables can bend at a sharper radius than cheaper cables.
 
LadyInBed said:
"It was becoming increasingly more difficult to engage reverse, until it got to the stage where it became impossible

So we installed new control cables"

So you changed the cables again?
Click to expand...

Yes, but the first replacement of the control cable did not result in any improvement - I think reverse gear engaged maybe twice after the cable was installed.
The gear control cable is a Morse 64C and its a pretty large cable - the first replacement was not a Morse (and was black in colour), the second replacement is , I believe, Morse (and is red in colour, the same as the original) - so it may be that the first replacement cable was just not up to the task.

Also, the cable clamp on the first replacement (at the engine end) was not located exactly in the 'indented' section of the cable - apparently this is critical, so maybe the cable was able to move - although I never saw any evidence of the cable moving
 
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