Penta MD22 - Black soot in water, NO smoke

[workavoidance]

Hi all,

We have a MD22 (Perkins Prima) which has about 3000 engine hours. She has been shadowed by a generator most of her life so has not been idling for long to charge batteries.

In the last couple of months the generator has been playing up and we've had to use the engine at 1300 rpm to charge batteries on cloudy days.

Just a few days ago I was maneuvering in a marina and needed to apply high rpm to kick the stern out. A large mount of black water came out of the exhaust, no smoke but lots of water. We quickly anchored and checked that it wasn't oil - it wasn't. No black smoke at all.

We took the boat out for a spin and the engine ran clean at 1800-2200 rpm, no smoke and clean water. After an hour of warm-up I slowly took the engine up to 2600 rpm and took a sample of exhaust water. There was no smoke but the water was full of soot, turning it brown/black looking. We continued to run her 'hot' for 30 minutes (italian tune-up) and the amount of soot has decreased slightly.

One thing I have noticed is that if I do idle her for a while (when anchoring etc.) and then rev her fairly hard she will kick out white smoke for a few seconds before it becomes clear. I suspect that is a faulty injector.

Does anyone have comments or recommendations?

Thanks

[skipperpete]

Originally Posted by workavoidance

Hi all,



We have a MD22 (Perkins Prima) which has about 3000 engine hours. She has been shadowed by a generator most of her life so has not been idling for long to charge batteries.



In the last couple of months the generator has been playing up and we've had to use the engine at 1300 rpm to charge batteries on cloudy days.



Just a few days ago I was maneuvering in a marina and needed to apply high rpm to kick the stern out. A large mount of black water came out of the exhaust, no smoke but lots of water. We quickly anchored and checked that it wasn't oil - it wasn't. No black smoke at all.



We took the boat out for a spin and the engine ran clean at 1800-2200 rpm, no smoke and clean water. After an hour of warm-up I slowly took the engine up to 2600 rpm and took a sample of exhaust water. There was no smoke but the water was full of soot, turning it brown/black looking. We continued to run her 'hot' for 30 minutes (italian tune-up) and the amount of soot has decreased slightly.



One thing I have noticed is that if I do idle her for a while (when anchoring etc.) and then rev her fairly hard she will kick out white smoke for a few seconds before it becomes clear. I suspect that is a faulty injector.



Does anyone have comments or recommendations?



Thanks

It's probably best to start with the time honored process of elimination....... blocked mixer elbow: restricted air intake: turbo? dirty propeller, then maybe move on to the injectors, it's possible that one or more has developed a problem but if this was the case, the engine wouldn't run smoothly and the exhaust would probably be a bit smoky. The non smoky exhaust is hard to explain given the black soot in the cooling raw water.
Do you have any large pto loads such as high output alternators or engine driven refrig compressor?

[Compass790]

Don't know yr engine but have you done tappets? How long since injectors were checked?
I, like skipperpete, am puzzled by the absence of smoke. Maybe injector is blowing a stream.
But yes suspicion would fall on injectors after checks that skipperpete mentioned

[workavoidance]

Thanks for the input guys, I was rather confused by it all. The propeller is almost certainly a bit dirty, but I doubt it's that bad, the hull is also far from clean.

The only smoke I see is white, and only after I've been idling for a while and then rev'ing hard. For example, in the Panama canal we weren't allowed to turn off the engine and had long long periods of idling followed by very intense moments of maneuvering.... large clouds of white smoke came out of the exhaust for a few seconds and then back to normal.

I'll take the hose of the elbow and have a look, it's been about a year since I last looked so it's worth it anyway. I checked, cleaned and replaced the air-intake a few months ago and it all looked good. I'll check it again to be sure. We don't have a turbo.

She sounds smooth enough when running and not much loss of power. With a perfectly clean hull and propeller she will max at about 2800 rpm, now she caps out at 2600 which I put down to fouling. Boat speedwise she is a little slower, but again, I assume that is fouling.

There is no significant additional loads on the engine, she is 55hp and only running the factory standard 60amp alternator. What's more, we'd just left shore power so the batteries were at 100% and I doubt there was any load on the alternator at all. No additional devices like fridges etc.

I'm leaning on injectors. I've no idea the last time they were checked or cleaned. It shouldn't be too hard to find someone to service them in Fiji - I just remember reading something about the MD22P injectors needing special care when removing, or replacing. I need to research more.

Cheers!

[skipperpete]

Thanks for the update workavoidance. Ideally use a dedicated injector puller to get them out but if that's not available , you can get a bid flat washer with an I.d that matches the thread diameter on the injector then remove the injector pipe.... put the washer on the injector.... reattach the injector pipe and use 2 levers under the washer to gently ease out the injector. 2 large flat wrenches work quite well as levers.

[coastalexplorer]

to remove injectors from a Volvo, drain down half of the coolant IF it is a fresh water cooled engine. other wise try to eliminate the sea water, pour penetrating oil product into the copper socket pressed into the cylinder head and leave over night.


It is reasonably simple to make a puller, Ask the local Bosch dealer for a spare union nut that holds the fuel line on. buy one of the longest 1/2 bolts you can find (9 + inches preferably) usually bolts have a standard 1-1/2 inches of thread. cut this off and have a machine shop drill and tap 1/4" NC thread in the end. Also ask them the supply a piece of round stock with a 17/32 hole through it. using a 1/4" Allan head cap screw assemble these parts into a puller.


Remove the fuel line and attach the union nut of the puller and then carefully try to extract the injector: as straight as possible. I hope that you do not remove the copper. I have been told it requires special tools to reinstall it if you do.


Then take the injectors to a Bosch service center to be rebuilt.

NOT VOLVO!!!

[Dsmnswan]

I had the same issue with my Perkins turned out to be a dirty prop Very disconcerting when you first see it though.

Regards. Dean

[skipperpete]

Originally Posted by coastalexplorer

to remove injectors from a Volvo, drain down half of the coolant IF it is a fresh water cooled engine. other wise try to eliminate the sea water, pour penetrating oil product into the copper socket pressed into the cylinder head and leave over night.


It is reasonably simple to make a puller, Ask the local Bosch dealer for a spare union nut that holds the fuel line on. buy one of the longest 1/2 bolts you can find (9 + inches preferably) usually bolts have a standard 1-1/2 inches of thread. cut this off and have a machine shop drill and tap 1/4" NC thread in the end. Also ask them the supply a piece of round stock with a 17/32 hole through it. using a 1/4" Allan head cap screw assemble these parts into a puller.


Remove the fuel line and attach the union nut of the puller and then carefully try to extract the injector: as straight as possible. I hope that you do not remove the copper. I have been told it requires special tools to reinstall it if you do.


Then take the injectors to a Bosch service center to be rebuilt.

NOT VOLVO!!!

All good advice coastalexplorer but this is a volvo by name only and really a Perkins (prima) . No pesky copper injector sleeves and Orings on this engine, but your advice should be carefully noted by those who own genuine Volvo Penta's and wish to avoid flooding the cylinders with cooling water.

[Pete7]

Originally Posted by workavoidance

Thanks for the input guys, I was rather confused by it all. The propeller is almost certainly a bit dirty, but I doubt it's that bad, the hull is also far from clean.

That could be enough to cause the problem from the extra drag on the hull and prop.

Think I would pressure wash the hull and polish the prop before taking out the injectors.

Pete

[Compass790]

Originally Posted by Pete7

That could be enough to cause the problem from the extra drag on the hull and prop.

Think I would pressure wash the hull and polish the prop before taking out the injectors.

Pete

Yes I would agree with this is the best starting point especially if injector removal is problematic