KAD43 Problem - Part 3

msimms

Well-Known Member
Joined
11 Sep 2002
Messages
430
Location
Boat: Chichester Marina
Visit site
Following on from Part Two we went out Saturday morning to see what effect the reconditioned injectors made. There was a notable improvement. Revs were up to 3600 from 3400 and there was no discolouration seen in the exhaust gasses in the water. The revs are still down on the starboard engine which manages 3800 (with port at 3600). There was still white smoke, about the same as before. The transom still got soot on the port side but noticably less than before.

Friends who came out with us on their boat noticed that that our exhausts looked different. When observed from the bathing platform looking down the bubbles looked much the same. Peering over the platform the bubbles exiting the port engine look to be coming not only from the exhaust but from all around the leg. I took a short video from the lock to try and show the difference but couldn't really get the right view. You can see a difference though. The engines had only just been started so there is a little smoke in the video but they've always done that when cold with no load.



I've looked at the workshop manual and can't see anywhere that the exhaust can leak from other than the bellows. However, this is a brand new bellows. It was replaced as the previous one had come off from the leg side. We think that the jubilee clip had failed.

I'm now wondering if something could have got inside the exhaust whilst the bellows was off and caused a partial blockage. When we went out for the first trip the pressure built such that it's now split the new bellows. Anyone think this is a possibility?

Would using the boat in this condition for a couple of shortish trips - at reduced revs of say 3000 - be okay? Temperatures and pressures are all good, both engines sound the same, it's now just a dirty transom and a little white smoke.
 
Just dont understand why you dont measure the boost! If thats ok it eliminate a lot of errors like clogged intercooler, bad turbocharger ,clogged exhaust and air leacage!

If the boost is high that indicates bad engine efficancy an plenty fuel!

If the boost is ok then you try other things. If the boost is low you measure the back pressure on the turbo. If thats ok chek the pressure before intercooler and so on. Its easy!
 
If the bellows have split under pressure, it sounds like you have a blockage within the passages of the sterndrive. Are the rubber flaps on the exhaust outlet ok? Perhaps you have nest of little critters in there:rolleyes:

Eddie
 
If the bellows have split under pressure, it sounds like you have a blockage within the passages of the sterndrive. Are the rubber flaps on the exhaust outlet ok? Perhaps you have nest of little critters in there:rolleyes:

Eddie

The flaps raise okay and there's a good amount of exhaust gasses exiting them. It's also bubbling up from all around the leg which makes me think the bellows have failed. Last time it failed it was off for a good few weeks before it was replaced. Time I suppose for something(s) to get in and cause a blockage. Obviously there was nothing apparant when we lifted the boat and put on the new bellows. The leg was just lifted to replace the bellows and not removed.

The legs are due there annual service in June which will allow a full and thorough inspection.
 
Just dont understand why you dont measure the boost! If thats ok it eliminate a lot of errors like clogged intercooler, bad turbocharger ,clogged exhaust and air leacage!

If the boost is high that indicates bad engine efficancy an plenty fuel!

If the boost is ok then you try other things. If the boost is low you measure the back pressure on the turbo. If thats ok chek the pressure before intercooler and so on. Its easy!

Unfortunatly I don't have Volvo tooling to be able to carry out out those tests.

Having now noticed a physical difference to the way the exhaust gasses are venting, it seems that should be next to be investigated. Even if it turns out to be unrelated I still want to get it fixed.
 
Top