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Loss of power volvo 2020B

L

Les Heath

New member
I have a Volvo 2020B diesel in my Centaur yacht. Recently whilst out for a sail, although initially the engine ran well and at 2000 revs, after restarting on the way back the engine lacked power and would only achieve 1500 revs under power. It will rev over 3000 out of gear.There is blue smoke coming from the exhaust.I have cleaned soot and sludge from the exhaust elbow and the heat exchanger and changed the CAV filter, but no difference. Can anyone help diagnose the problem , please.
Les
 
Many thanks, but I will try changing the engine fuel filter element first. I have changed the CAV filter, so best change the other filter first. I will let you know how I get on.

Les
 
What kind of prop do you have?
A feathering one that did not feather as supposed when starting the engine after sail?
Take a dive and check the prop.
 
Yes thanks , I have checked the prop. which is a normal 3 blade ( non feathering type) as I initially thought this may have been fouled, but it is clean , so I assume it is probably a fuel problem.

Les
 
I have now changed the fuel filter element on the engine, but no difference. Will try changing the lift pump next week, to see if that is the problem.

Les
 
Changing bits and pieces without knowing why is never good for either the wallet or the mind.
Start the engine, put it in gear and go.
Increase throttle until engine starts 'butting', around 1500rpm.
Then open, one at a time the nut on the injector for the pressure line.
That cylinder will then drop out.
If no or little reaction on one cylinder, probably an injector problem.
If rev drops the same on both cylinders, I would suspect a 'common' problem like injector pump or supply.
Disconnect the return line and let it run into a canister. If return stops, you have a supply problem.
 
We have checked disconnecting the Injectors one by one , whilst under power and find that the third Injector did not stop the engine, whilst the others did. I have had the Injector serviced by the local Bosch agent and they have replaced the nozzle. Hopefully this will solve the problem, but I am having the compression on that cylinder tested first , before putting the Injector back. If the compression is poor, then it looks as though the head will have to come off. I have my fingers crossed!!!

Les
 
Well, we checked the compression today on number 3 cylinder and there was not any!!! So looks like an exhaust valve has caused the lack of power all along, so the head will have to come off , unfortunately. Anyone know where I can buy a reasonably priced Volvo Penta 2020B head gasket etc. in the UK They seem very expensive

I will advise further after the exhaust valve has been looked at.
Les.

Les
 
The work on my engine has now been completed . The head was removed to showed a very badly rusted exhaust valve with missing bits ( number 3 cylinder) , so no wonder the engine lacked power. The engine had been smoking a little previously and now I know why. Anyhow the engine is now running again and I am looking forward to speed trials when the boat is back in the water end April. I am told that the valve has been affected over the years by water ( number 3 cylinder being closest to the exhaust) , so in future I will detach the exhaust hose when laying up and make sure that the engine compression is left with number 3 at top of compression cycle.
Thanks to all those who assisted.
 
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