Diesel Engine Smoking

[zeehag]

black also comes from not using engine much for a while. what chief engineer said.

[MarkSF]

Originally Posted by Russt1950

I am looking to buy a 36 Catalina boat. Everything on the boat is ok except, I went back today to run the motor and notice black smoke coming from the exhaust. The owner has not used the boat in awhile. I ran it at 2200rpms and at first the smoke was really thick. After a while it started to ease up. Also, the temp started to rise a little over 180 and then there was white smoke or steam coming from the exhaust. The motor only has 650 hrs on it and I would to get this boat, but don't know if this is a serious problem or not. Any advice appreciated.
The motor is a Universal M35B.

Thanks, Russell

If this engine still has the 2.5" heat exchanger instead of the 3" then 180 degrees is normal at 2200 rpm. However, lots of steam is not. Was there water as well as steam? Was it a cold day? Maybe just normal condensing of vapour.

There shouldn't be any black smoke, ever. Never get a whisp of smoke out of mine. Something is wrong.

I do tend to get steam if everything is not tip top in the cooling system, as the cooling is a bit marginal with the smaller heat exchanger (Universal 24hp). Check the sea water strainer.

[Russt1950]

The boat has not been used in 8 months. I know the botton is really dirty, and I would guess the prop is as well. I think the black smoke is from not using the motor for a long time, and maybe some old fuel. The steam might be from clogged intake or something else. Thanks

[svBeBe]

Original Poster - Get a trusted diesel engine mechanic to check the engine...probably something is wrong...maybe major, maybe minor. Get a complete survey on the boat. There are potentially more expensive items that may need attention than the engine.

This forum is not the place to get opinions of your observations of the engine when you are looking to possibly purchase this boat.

You might try the following link to the Catalina 36 owners website for some additional information about the C36 and the Universal engine: Catalina 36/375 International Association

Don't buy it without a survey!

Bill

[Tropic Cat]

Originally Posted by defjef

Shiva has a Volvo MD17D - original installed new in 1986. The engine has over 4000 hrs. It has one major rebuild of the head, new injectors and so forth... did not have rings done.....

I believe the engine needs rings, but the oil tests fine...

I rebuilt one of my 1985 yanmar engines this year with the help of the marina's diesel mechanic. It was surprising how easy this was. On rings, as they get old they lose their springiness (is that a word?). My mechanic demonstrated the difference in how well the rings rebound after being compressed between my old and new set. It was significant. The old rings were so worn, he removed them from the piston with his finger tips.

You would notice the difference in performance, if you rebuilt the engine. Actually, I thoroughly enjoyed the learning experience as I hadn't got that involved with an engine in more than 40 years!

[delmarrey]

Originally Posted by Tropic Cat

I rebuilt one of my 1985 yanmar engines this year with the help of the marina's diesel mechanic. It was surprising how easy this was. On rings, as they get old they lose their springiness (is that a word?). My mechanic demonstrated the difference in how well the rings rebound after being compressed between my old and new set. It was significant. The old rings were so worn, he removed them from the piston with his finger tips.

You would notice the difference in performance, if you rebuilt the engine. Actually, I thoroughly enjoyed the learning experience as I hadn't got that involved with an engine in more than 40 years!

FYI -Springiness is actually called elasticity.

[cburger]

Originally Posted by defjef

Shiva has a Volvo MD17D - original installed new in 1986. The engine has over 4000 hrs. It has one major rebuild of the head, new injectors and so forth... did not have rings done.

In cold weather... the engine will start right up and put out dark grayish blue smoke. As the engone temp comes up to normal operating temp... 10 minutes or maybe 15... the smoke clears. When the engine is warn there is only a touch of smoke.

I believe the engine needs rings, but the oil tests fine... will do another test in a few weeks. Power seems fine, but fouled bottom and prop slows the boat a knot or more.

The smoke freaked me out when it first appeared... I think it's from the rings and when it heats up they seal better... Just a guess as I am not a mechanic. It's not worth it to me to undergo the expense.

When the engine gets old it may be time to repower. For now... she's fine.

Just a grouchy old guys 2 cents worth. My diesel was completely broken down for inspection prior to installation, 5000hrs. The mechanic indicated that the motor was just fine. My motor is doing the same as above, but considering she has sat for about two years, and did alot of idling for the test phase of the installation I am not too troubled by a little white smoke on start up. Diesels like to be run under load. I have been making a real effort in taking the motor out and running it hard, 80% max rpm for long periods. As a result I have noticed significant reduction in smoking and much easier starting. The classic auxilary diesel use in sailboats of long periods of dormancy and short periods of running can be a diesels wort enemy. So depending on how this motor was utilized the smoking may or may not be an issue. However considering the age consider the return on investment of tearing down, sweating the small stuff prematurely, after all it is a used boat and motor. So if you really like this vessel and after review of comparable vessels for sale it is within the range you might consider purchasing. FYI I wish my motor ran at 180, my gauge reads 209 under load. However something that I didn't see mentioned is that gauges go bad and can give bad reading all the time, especially if old as well as the senders. Had a brand new oil pressure gauge out of the box read zero just last week.