Engine smoke and sheen on the water

[Scubaseas]

Remember the how thick is the molecule experiment? One drop of oil will give you about a 6' circle of sheen. Unburnt fuel can give you sheen, Left over oils in the exhaust from you old engine can give you a sheen. Oils left over from assembly and now in the exhaust will give you sheen

Take the boat away from the dock and break in the motor like the Volvo manual says. Keep an eye on the oil level but you may not have a problem. Run it in for 20 or more hours and then let us know if there's an issue.

[Compass790]

You would assume rebuilders have done the timing correctly as they replaced the belt but everyone can make a mistake.
Don't know if that's the smoking gun but as said before it needs to be part of the diagnosis.
I'm doubtful it will be a compression issue with the easy starting but that needs to be ruled out as well.

Still following & agreeing with your logic thus far but we cud be both wrong!
Sometimes you smack yrself in the head as it seems so obvious after sum1 else points it out.
good luck again

[Cadence]

Originally Posted by Mastermuffin

Yea, i changed the oil after i noticed the sheen on the water, put Delo 15-W40. not sure if that's the best oil to use.

Have you consulted the dealer you purchased the engine from? I'll be redundant, two hours is not enough time for it to break in. Taking the engine apart piece by piece does not make sense at this point.

[LooseGoose]

The condition is known as slobbering. It happens to engines that are not sufficiently under load, and is the result of incomplete combustion accumulating a bit of unburnt fuel in the muffler and exhaust hoses. Diesel engines are designed to pkerate best at around 80% load.

On my boat, I take it out and run the engines at 80 % of rated rpm for 15 minutes or so before docking. It does them absolutely no harm and eliminates the sheen as well as most of the smoke at startup.

Advise that you take it out, warm it up to full operating temperature, then run at 80% or higher load for a half hour then check your rexhaust. Thats where the engine is optimized and designed to run continuously. Its not like a gasoline engine which can idle around all day loafing around.

[Lynall]

Not often I think of a reply as most posts are way over my head boaty wise!


But engines I know a little, and I have a boat with two MD22L engines, so my observations are as follows.
1, they are direct injection which is why they start well, and why they are noisy at idle.
2, and this is most relevant to the op, they are naturally aspirated and the ops engine appears to have a boost compensator fitted to the top of the injector pump, and I was under the impressioon these were fitted to turbo engines only, in this case the TAMD22.
3, the pumps are Bosch VE units fitted to many makes of engines/vehicles world wide
4, pump timing, and lift at tdc is very important, timing pins will get you close but not close enough.


I will try and attach some pics of my engines and you can see the inj pumps have no compensator fitted, I would hazard a guess off boost the turbo engine/inj pump uses no more fuel than the n/a version, but it might be enough of a difference to make the sheen?

[Lynall]

One more pic,
Maybe worth checking the cambelt timing as well? easy to do, all you need is some drill bits, and a cheap boach ve kit off ebay to check pump lift is about 25 gbp, unsure of exchange rate but under 30 dollars would be my guess, loads of vids on youtube.

[Lepke]

Compression rings in their design, are forced out and create a tighter seal with greater pressures. Also over time carbon builds behind the rings, keeping them from retracting as much. Until the engine gets some extended time at near full power, the rings won't experience enough pressure to fully seat.

[le chat beaute]

Advice to add additional hours on motor is a good one. You might check that the thermostat is operating correctly as a cold motor with an open thermostat will exhibit these symptoms until the motor has heated up under load. Difficult to get the motor warm without a load. The motor sounds great and idles nicely so compression should not be an issue. Temperature is my two cents worth. Aaaah welcome to boat life.

[skenn_ie]

If there was a turbo, that would be my first point of suspicion. Turbos don't have oil seals, so they will always lose a little oil. Next, valve seals/guides. Not all engines have seals on the valve guides. Next, head gasket. Next, did the person that rebuilt it, hone the bores (glaze bust) and replace the rings ?
Most people recognise that rebuilds vary vastly. I once looked at an engine that was supposedly rebuilt, but there was absolutely no compression so I walked away.

[gonesail]

I was going to say: check the exhaust elbow .. but that would be for a yanmar

[Mastermuffin]

Originally Posted by LooseGoose

The condition is known as slobbering. It happens to engines that are not sufficiently under load, and is the result of incomplete combustion accumulating a bit of unburnt fuel in the muffler and exhaust hoses. Diesel engines are designed to pkerate best at around 80% load.

On my boat, I take it out and run the engines at 80 % of rated rpm for 15 minutes or so before docking. It does them absolutely no harm and eliminates the sheen as well as most of the smoke at startup.

Advise that you take it out, warm it up to full operating temperature, then run at 80% or higher load for a half hour then check your rexhaust. Thats where the engine is optimized and designed to run continuously. Its not like a gasoline engine which can idle around all day loafing around.

Ive taken it out and even under load i can see a trail of sheen behind the boat though it seems to get batter. Also, i cant get the engine to go over 2600 rpm without a bunch of black smoke. I shouldn't be over propped, my last engine (50 hp) was the same with different injectors and pump and would rev to 3000 no problem. This one is rated at 59 hp and max rpm of 4000.

Originally Posted by Lynall

One more pic,
Maybe worth checking the cambelt timing as well? easy to do, all you need is some drill bits, and a cheap boach ve kit off ebay to check pump lift is about 25 gbp, unsure of exchange rate but under 30 dollars would be my guess, loads of vids on youtube.

Thanks for the info, are yours the 50 hp version? the 59 hp version has different injectors/ high pressure pump. Also if you could link me to a kit for the injector timing that would be awesome.



Also, when cold do these engines tend to throw out white diesel smoke/ run a bit rough. I think this engine is starting to miss on a cylinder when cold because it has a bit of a hiccup for the first 5 seconds.

[Compass790]

[QUOTE=Mastermuffin;3297555]Ive taken it out and even under load i can see a trail of sheen behind the boat though it seems to get batter. Also, i cant get the engine to go over 2600 rpm without a bunch of black smoke. I shouldn't be over propped, my last engine (50 hp) was the same with different injectors and pump and would rev to 3000 no problem. This one is rated at 59 hp and max rpm of 4000.

I'd be very suspicious of low compression if you can only get to 2600rpm before it blows black smoke assuming there is no air restriction.
You cannot be overpropped if you have thge 50hp prop unless boat is dragging around a marine farm on the bottom.

[Cadence]

? Was the gearbox change and ratio. Going back to the OP I believe the engine has not been "broken in" .

[Mastermuffin]

Originally Posted by Cadence

? Was the gearbox change and ratio. Going back to the OP I believe the engine has not been "broken in" .

I used the same gearbox that came off of my previous engine, think the ratio is 2:1. not sure what prop size and pitch is.



Did a leakdown test when engine was cold


Cylinder 1: 16% leakage past rings
Cylinder 2: 10% leakage past rings
Cylinder 3: 10% leakage past rings
Cylinder 4 17% leakage past rings


Weird thing was cylinder 2 and 3 would sometimes have 60% leakage past the rings. i did the test multiple times and sometimes they wouldn't engage.



i get a compression tester today so maybe ill get a chance to test that tomorrow.

[Compass790]

No experience with leakdown test but think the engine is supposed to be as warm as it can be for compression test.
Guess you can google it.