kad300 to dpg drive problem

zt260

zt260

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www.ashmouldings.co.uk
Any thoughts about the following
Whilst moving my boat from York to hull marina on good Friday I lost drive to my starboard leg

we were approaching trent falls at approx. 25knots and the legs were at -4(go down to -7) when I put the boat into a 3/4 starboard turn,
We then had a sudden loss of power and the smell of burning rubber(suspected supercharger belt failure) I shut both engines down and had a quick look in engine bay all belts were still there.i then started the engines and found I only had propulsion on my port leg, and limped into the anchorage,After further checks I found that the starboard leg engages forward and reverse gear and the props lock in gear as they should but there is no drive to them,the engine starts and seems to run okay,

I am thinking of possible UJ failure,Is there a shear pin between the drive and the engine?

After limping down the humber at 6 knots I managed to get to hull and the boat is hopefully being lifted Friday

Any thoughts would be appreciated

regds ashley
 
zt260 said:
Any thoughts about the following
Whilst moving my boat from York to hull marina on good Friday I lost drive to my starboard leg

we were approaching trent falls at approx. 25knots and the legs were at -4(go down to -7) when I put the boat into a 3/4 starboard turn,
We then had a sudden loss of power and the smell of burning rubber(suspected supercharger belt failure) I shut both engines down and had a quick look in engine bay all belts were still there.i then started the engines and found I only had propulsion on my port leg, and limped into the anchorage,After further checks I found that the starboard leg engages forward and reverse gear and the props lock in gear as they should but there is no drive to them,the engine starts and seems to run okay,

I am thinking of possible UJ failure,Is there a shear pin between the drive and the engine?

After limping down the humber at 6 knots I managed to get to hull and the boat is hopefully being lifted Friday

Any thoughts would be appreciated

regds ashley
Click to expand...

Possible failure of drive dampener (attached to flywheel)
 
I could be wrong, but I thought the oscillation damper attached to the flywheel was a solid disc with a moving sprung section in the middle.

Another possibility could be the rubber bushes inside the props: these can separate, resulting in the outside section with the blades rotating independently of the inner splined hub (under load).

Oscillation damper:

damper.png
 
FlowerPower said:
I could be wrong, but I thought the oscillation damper attached to the flywheel was a solid disc with a moving sprung section in the middle
Click to expand...

Some are sprung plated and some are rubber bonded to a plate, that's where the burning rubber smell could have come from, unlikely to be prop bushes burning under water.
 
Thanks for the replies I did wonder about the props but when I put it in gear I couldn't spin the props by hand.If it is the damper plate I assume it's engine out

Regds ashley
 
If you cannot spin the props both ways when in gear there should still be drive so check again as you can spin the props only one way when the engine is in gear as the cone is making the drive.
There is a shear tube in the vertical gear case that's designed to break when you hit an object or run aground making prop contact with something .
 
zt260 said:
Thanks for the replies I did wonder about the props but when I put it in gear I couldn't spin the props by hand.If it is the damper plate I assume it's engine out
Regds ashley
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There is a lot more force going through the prop hub than you can possibly test by hand.

As to the damper plate, it depends how much room there is to work around the engines, and whether they could be moved forwards enough. On many boats, it would be engine out to sort.

A very simple test would be to swap the props from port to starboard, and see if the problem changes sides.
 
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After lifting the boat it would appear that the upper gear set has shed a few teeth,
There is no sign of any prop damage or leg damage,
Anybody else had this happen if so did you find any reason for it

regds ashley
 
Wow, I've not heard of that before, other than when someone has hit something with Stainless Steel propellers, which don't bend much, but even then I would expect some sign of damage externally.
I'm assuming that the oil level inside the drive was correct, correct type of oil used, and that it wasn't contaminated by water.
 
The oil was changed about 50hrs ago I used volvo oil,when I pop the bellow to check the uj there was alot of clear drive oil draining out that must have come from the upper gear drive.I then removed gear shifter face plate and saw the upper gear drive minus some teeth and the oil was grey and full of filings it also smelt burnt.
I assume there must be an oil seal between the uj shaft and upper gear if that had failed the upper gear could have been running dry?that could explain the clear oil in the uj area

Regds ashley
 
zt260 said:
The oil was changed about 50hrs ago I used volvo oil,when I pop the bellow to check the uj there was alot of clear drive oil draining out that must have come from the upper gear drive.I then removed gear shifter face plate and saw the upper gear drive minus some teeth and the oil was grey and full of filings it also smelt burnt.
I assume there must be an oil seal between the uj shaft and upper gear if that had failed the upper gear could have been running dry?that could explain the clear oil in the uj area

Regds ashley
Click to expand...

Oil in bellows area means failure of top seal, there is a wear ring inside the top housing that scores, this is why a pressure test is essential on a service. If the upper gear set has smashed up and there are metal filings in the oil there is now every chance there will be damage to the drive cone, all upper and lower bearings as the oil circulates around the drives when running. The drive must be totally stripped down and cleaned and examined, no point in buying an upper housing for the lower half to fail later due to unseen damage, don't let anyone tell you otherwise . The failure could be due to the loss of oil dumped in the bellows. How much was drained off after? This will give an idea if you overfilled it when you serviced the drive.
 
volvopaul said:
Oil in bellows area means failure of top seal, there is a wear ring inside the top housing that scores, this is why a pressure test is essential on a service. If the upper gear set has smashed up and there are metal filings in the oil there is now every chance there will be damage to the drive cone, all upper and lower bearings as the oil circulates around the drives when running. The drive must be totally stripped down and cleaned and examined, no point in buying an upper housing for the lower half to fail later due to unseen damage, don't let anyone tell you otherwise . The failure could be due to the loss of oil dumped in the bellows. How much was drained off after? This will give an idea if you overfilled it when you serviced the drive.
Click to expand...

This is very god advice, I had my upper gear break down in 2005 with a lot of metal floating around and even though I got penta to replace the upper drive at their expense they would not replace the lower drive in spite my concerns it was damages as a result of the upper gear breaking down. I was however told it was fine but now the lower gears are wearing out and getting to their end of life. I have 2 legs and the other one has just been stripped fully due to hitting an underwater floating object with SS props but without internal damage and expected to have at least another 10 yrs of average use in them.
 
I've not drained the leg yet,I would say there was approx 100 to 200ml of oil in the bellows.I will hopefully be removing the leg on Saturday

Regds ashley
 
Thanks for all the thoughts on this,a complete strip down and new bearings lower and upper and a new gearset seem to be on the cards

Regds ashley
 
Crikey, Never heard of this before (but what would I know?) - Please do keep us updated. Sorry to hear what happened.
 
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