The mistery slick


svperegrinus@yahoo.com
 

Hello,

I'd like your opinion on this engine issue.

When we bought the boat in 2012, about every 30 seconds you could see a drop of oil come out from underwater, on the boat's exhaust.  Like a flower opening, you saw a dot which then became a small circle.  The engine had 2000 hrs.

The engine now has 3,525 hours.  Some people think the white smoke that comes out of it is normal, but I think it is a bit much.  But what worries me is that the oil in the water is not acceptable.  I am pretty sure the other boats don't do this.  Look at the attached photo, taken 5 minutes after the engine was turned off.  Zero oil on the port side, and zero oil around the surrounding boats.

Some stats from the last 58 hours of engine use (from eastern Crete to Hyères, with stops along the way, 1171 miles if we had motored in straight lines, but we obviously sailed most of the way):
 - fuel consumed: 310 liters (includes 6 hours of genset use at 3/4 load)
 - oil added: 1/2 of 1 quart

Many thanks in advance for your thoughts.  I've asked for a mechanic to come by to see the 100HP Yanmar.

Cheers,

Peregrinus
SM2K N. 350 (2002)
Hyères


Ian Park
 

When I had the engine mounts replaced and other work done on the engine in Martinique, the Amel engineer started it and told me I would either need to clean the injectors or preferably put in new ones (but not out here! They’re too expensive. Get them in Europe). Reason = he said look at the exhaust, there are traces of diesel coming out with the water - dirty injectors.

It would be worth verifying this, either from other owners with more experience or an engineer. My Perkins has done 5,500 miles now.

Ian

Ocean Hobo SN 96 Antigua.


greatketch@...
 

If you were looking at motor oil in the exhaust you would see a fairly rapid loss of oil level in the crankcase, and likely a LOT of smoke. 

I'll second Ian's suggestion that what you are seeing is actually diesel fuel.  You mention a bit of smoke also, and that would back up that suggestion.  One (or more!) injectors are either sticking open, or have a bad spray pattern and the fuel is not fully burning.  If this is happening a LOT you can actually see an increase in the level of oil in the crankcase as it gets diluted with diesel fuel.  This would be VERY bad.

You might be able to narrow it down to which cylinder by cracking the nut holding the fuel line to each injector in turn while the engine is idling.  When you open the fuel line to a "good" cylinder, the engine will slow and run rougher.  A "bad" cylinder will show little or no change.  It could be more than one.  Injectors can be damaged by dirt, or water in the fuel, so there could be a common cause.

This is important to get fixed.  When a cylinder wall is wet with unburned diesel fuel the lubricating oil is washed off, and wear is greatly accelerated.  Cleaning/Testing/Repairing/Rebuilding injectors can be done, but it is rather specialized work requiring high precision tools and expensive test beds to do correctly.  Not the job for the island mechanic, even if he thinks he can.  

If you do replace them with new, save the old and have them rebuilt by a specialist shop when you can.  Spare injectors are not a bad thing to have!

Bill Kinney
SM160, Harmonie
Rock Sound, Eleuthera, Bahamas

---In amelyachtowners@..., <parkianj@...> wrote :

When I had the engine mounts replaced and other work done on the engine in Martinique, the Amel engineer started it and told me I would either need to clean the injectors or preferably put in new ones (but not out here! They’re too expensive. Get them in Europe). Reason = he said look at the exhaust, there are traces of diesel coming out with the water - dirty injectors.

It would be worth verifying this, either from other owners with more experience or an engineer. My Perkins has done 5,500 miles now.

Ian

Ocean Hobo SN 96 Antigua.


svperegrinus@yahoo.com
 

Thank you Ian and Bill.

The injector nozzles on all 4 cylinders were replaced with new 125 hours ago, as were the racor filters and the fuel filter.  Today the racor filters and their "bubble" look pristine.

I am pretty sure what we see in the water is fuel.  Since the water here is so clean and still, this afternoon I ran an experiment as suggested by Gary of Adagio: take diesel-absorbing pads and check if they absorb the slick.  They do.

Maybe we are down to low cylinder compression in one or more of them, for whatever reason, or maybe we have a bad injector.

Best,