Volvo Penta AD31B duoprop, problems??

Grajan

Member
Joined
24 Jun 2004
Messages
344
Location
N. Ayrshire
Visit site
I am in the process of purchasing a Hardy Seawings 234 and as I have been a “rag & stick” man up till now I don’t know a lot about VP outdrive diesel units

After sea trials I noticed that there was more than several oil splashes on the transom adjacent to the engine, port side (not there before we went out, but obviously not a new happening due to the condition of the surrounding area) this was explained to me as being normal, caused by the stern sitting down on acceleration and oil being blown out of crankcase breather as it drained to the back of the engine?

Oil levels were okay before and after the trial, engine has done 900 hours and revs to 3700 under load oil pressure cold 70lbs +, hot 30+ hot at tickover

There was a tube that contained the gear? cable that leaked water when pushed down to bearer level, is there no external seal? Lastly and possibly most important is when selecting reverse it appears to engage, as props turn but it takes about 8 seconds before increasing the revs, gives reverse thrust. the current owner has got used to this situation but my marina berth is at the bottom of a blind alley and mistiming the 8 second delay will find me on top of the main marina walkway!! The current owner tells me that the gear linkage is checked on an annual basis by a VP dealer and that the delay is possibly due to mis adjustment at some time but will improve with use???

Having reached the age where reliability ranks higher than adventure I need to know that I have a reliable engine and drive and would appreciate any guidance on these matters

Brgds Graham G
 

DAVIDO

New member
Joined
25 Aug 2006
Messages
952
Location
Cardiff
Visit site
When we bought our boat with AD41s there were a number of issues which i didnt take seriously enough. Subsequently costing a lot of money to sort. If i were in that situation again i would pay a suitably qualified engineer to provide a complete report on engine/s and leg/s. That could then be used as a bargaining tool should he find problems.
 

spannerman

Well-known member
Joined
30 Nov 2002
Messages
3,151
Visit site
There is no external seal on the rubber tube it relies on being above the water line.
As regards the delay in shifting this sounds like the cone in the gearbox is worn. I would insist that the cone is replaced and the gears inspected, before completing the purchase, or the price reduced accordingly.
Get a quote from for the job from a good engineer..
 

Chris_d

Well-known member
Joined
15 Jun 2001
Messages
4,737
Location
Oxfordshire
Visit site
I've got 2 AD31's with none of the problems you describe, so definately not normal. The 8 second delay thing sounds ominous, either the problems are fixed before you buy or walk away.
 

Viscount

Member
Joined
12 Nov 2003
Messages
458
Location
Scotland
Visit site
I agree with Chris_d. Also, I had a problem with one engine blowing oil out the crankcase breather; the solution from VP was to implement a modification that changes away from an open breathing system to closed. This involves getting rid of the breather filter and relief valve and feeding the breathing into the rear rocker cover. Don't know the cost as it was a warranty issue.
 

mont

New member
Joined
6 Nov 2005
Messages
296
Location
Boat sold ! me Leeds
Visit site
Could be just poorly adjusted - was on mine with identical problem after VP fitted new cables. Engaged forward immediately (too quick) but astern needed time or revs. Could be too much slack. Control cables need to be set up correctly and its a tedious job usually requiring a lift out.
Could (as said) though be worn cone - £1500 plus minimum.

Get the owner to resolve before handing over money - he is clearly fully aware of problem. Then get it checked to ensure its been sorted properly.
 
Top