Forward drive not engaging - Volvo MD2020

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skiperr

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I have an intermittent problem trying to engage forward gear after reversing. A nasty problem since the only time I engage reverse is maneouvering in tight spots in the marina. After a few scary moments I manage to engage forward and then all is fine. Otherwise the engine runs fine.

My engine is a 10 yr old Volvo MD2020 with shaft drive in a Jeanneau S/O 32.

Any thoughts out there before call out the Volvo engineer?
 
First thing to do is disconnect the gear cable link and see how it behaves operating the lever on the gearbox. It's not unusual for the morse control to be out of alignment.
Also, are you moving from reverse to forward with the engine running? It's common for the gearboxes to 'stick' when left in reverse to stop the prop spinning.
 
If you find the answer, I'll be delighted.
I have had this issue from new and no one seems to know the answer. I have to pause after moving the lever forward to engage forward gear. If I open the throttle too soon, the engine revs rise, but no drive.
It's a Volvo D 1-30B. I believe that the forward and reverse propulsion operates on entirely different principles, which is presumably why reverse engages instantaneously. I think I'm right in saying that reverse works by way of a brake band whereas forward works by way of some sort of clutch.
I've changed the oil, adjusted the cables, no signs of dirty oil or bits in the oil and asked lots of engineers,all to no avail.
Good luck with your enquiry, I'm watching with interest.
CJ
 
I had a very similar problem with my Hurth gearbox - could engage astern gear but not forward. Started as an intermittent problem but over a few weeks became harder to find forward gear until couldnt find it all.

I removed the control cable from the gearbox and tried to engage gear by moving the control on the box - found reverse no problem but wouldnt engage in forward so that ruled out cable problems.

After a bit of Googling it started to become clear that the problem was with either the compression plate or the gearbox itself. We removed both and the compression plate seemed in good order.

I dropped the oil out of the gearbox and found that it was black which kind of confirmed that there was a problem.

As the box was over 20 yrs old, I didnt see too much point in having it checked out / reconditioned as the cost of this was about two thirds the cost of a new box.

New box fitted and working well....fingers crossed.
 
The MD2020 has an MS2 gearbox

Internally the gear selection is very simple.

I'd agree that the first thing to check is the cable adjustment.


The D1 30 has i think you will find a MS 10 gearbox ... a very very different and much more complex animal


MS2


MS 10
 
VicS, thanks for the link. I don't think I'll venture inside there any time soon!
I will retire to the sidelines now, as I don't want to hijack the original thread.
CJ
 
I had exactly this in 2003 on a Volvo 2040 saildrive (new 2001).

After detailed inspection Volvo engineer said it was the almost new feathering propeller that was faulty.

Sent feathering prop back to Germany with a stroppy letter.

Quickly fitted a folding prop to get the boat back in the water. Same problem. This time Volvo said the clutch must be giving intermitant problems. Ended up paying for a reconditioned gearbox to get the boat back in the water quickly.

Got a polite letter back from variprop stating they could not find anything wrong but had checked it all over, serviced it , polished the blades etc but had to charge me a service & P & p fee. IIRC the charge was v reasonable. Embarrassed I just paid the full invoice amount.

This was the 5th nail in volvo's coffin on 2 new boats. Now will only buy a boat with Yanmar parts.
 
As Ruffles and VicS say, check the adjustment first with the throttle cable removed at the gearbox end.

Not sure if this will work.. It's a small video I made showing how the cones work.. (filmed whilst the grearbox was out and I had fitted the new saildrive diaphragm).

Link to gearbox cone demo on SkyDrive
 
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Martin_J said:
As Ruffles and VicS say, check the adjustment first with the throttle cable removed at the gearbox end.

Not sure if this will work.. It's a small video I made showing how the cones work.. (filmed whilst the grearbox was out and I had fitted the new saildrive diaphragm).

Link to gearbox cone demo on SkyDrive
Click to expand...

:cool:

Exactly what can be deduced from the exploded diagram. Outboard gear boxes work very similarly except that they have dog clutches rather than cones.

Please can you make a similar video to show how the MS 10 box works. ;)
 
If you look closely at the video you might also see why accuracy of end point adjustment is needed (and not just the neutral point).

You can see that once 'in gear' the moving arm releases itself slightly from the cones so as not to be rubbing permanently on the cones.

If it stays in contact all the time then you might find (previously unexplained) gold coloured dregs in the oil.

(Thanks for testing the link VicS... I'd always wondered myself what the cones actually did)..
 
Thanks all. Seems like my first step is to go look to see if I can make any sense of the cables and alignment to see if I can do what's suggested. I'll also check the oil condition whilst i'm there.

Keep you posted.
 
Getting the neutral point correct is usually quite an easy adjustment (a threaded adjuster at the engine fitting)...

If however the end to end throw is not quite right (either too little or too much) then the fix is not quite so easy. That could then be a case of taking the throttle lever assembly apart and pinning the cable into to another hole (although it can be even more complicated if you want an adjustment that would be between two holes).

Ceejay - End to end throw could still have been set slightly wrong from new..
 
I don't know if this is relevant, but a tangential view might help?

I had exactly this with a Yanmar gearbox. I've no idea if there is any similarity with the Volvo design.

Anyway - dismantling the gearbox showed that it was perfect. It just didn't work! As you say - always when manouvering into a berth.

I rigged up a jury control line, and I could 'feel' the box engaging through the rope, but there was just no drive :eek: :confused:.

Eventually, we discovered that Yanmar had experimented with the oil spec. This gearbox, contrary to all documentation, used a different oil to every other Yanmar box. It either should have been, or should not have been hypoid - can't remember which.

Anyway - a flush and a refill with the 'right' oil resulted in a working gearbox.

Just as a note, we had completely ruled out the oil as being the cause, so a lot of red herrings were investigated before coming back to the thing that 'was obviously OK' - but in fact wasn't.

FWIW

Jeff
 
Durcott, that's very interesting, as I first noticed the problem immediately after the very first oil change.....thanks for flagging that up....I'll re-visit that idea.
CJ
 
Sorry Ceejay :confused:
I only mentioned end stop adjustment because you said you had experienced the problem since new and it's something that could have been overlooked...

Ceejay said:
If you find the answer, I'll be delighted.
I have had this issue from new and no one seems to know the answer.
Click to expand...
 
Martin, no need to apologise, I think I confused the issue. I first noticed the problem after the first oil change, but I thought it possible that it might have been present from new. I thought that I may not have noticed earlier.
CJ
 
Ceejay said:
Durcott, that's very interesting, as I first noticed the problem immediately after the very first oil change.....thanks for flagging that up....I'll re-visit that idea.
CJ
Click to expand...

Following up on Durcott's point, I had a similar issue with a Yanmar 2gm gearbox. The cone clutch had worn over the years and my predecessor had filled the box with hypoid gear oil. This was far too slippy for the clutch which then failed to engage in forward - the direction that always wears first. But adjustment of the throw of the gear lever didnt work - we could then get it to engage forward and lost reverse instead.

In my case the wear had gone too far and Cellar Marine at Porthallow shimmed the clutch for me - something they did for fishing boats who couldnt afford / didnt want to pay the silly money involved in a new cone. Then we ran the gearbox on SAE 10 ordinary lube oil - problem completely gone and the box ran well for the rest of my ownership.
 
Bosun Higgs said:
How do you get this link to work? All I can get ( firefox and opera) is a little box top left which when clicked opens out a file list.
Click to expand...

Perseverance!

go down to the bottom of the file list click on MD2020 Gear box cones. The mp4 video down loads ... in Google chrome I then have to "Open" the file. Eventually it plays in Real player
 
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