White Smoke from Older Diesel at Higher RPMs

[kcoffey]

The engine in my boat is the original Volvo MD17D from 1985. All indications are that the engine has always been regularly maintained, has fairly low hours for its age (about 1500), and has neither required nor undergone any major surgery. The engine looks, starts, stops, runs, and sounds very well. The Volvo manual specs the engine at 3000 RPM, but I alway run it below 2500 RPM, usually at 2200 to 2300.

Once warm, the engine exhaust does have a very small amount of gray smoke when running between 1800 and 2300 RPM. Above 2400 or 2500 RPM, though, a larger amount of white smoke is visible in the exhaust.
Both the 2 micron Racor and the fine Volvo/Bosch filter on the engine are clean and almost new. Coolant and oil seem OK.

Any experience to suggest the cause of the white smoke?

[hamiam]

I will let the experts chime in here but i have experienced white smoke on 2 occasions. The first was after i warped the cylinder head. Big problem. There was ALOT of dense white smoke. The second time was as my engine started to run lean due to a clogged fuel filter. Less dense and less smoke all in. Very easy to fix. If you did have a head or cylinder problem you would proabably see the coolant level going down and your engine oil getting milky due to a combination of the 2 through the leaky head. If you not experiencing this that is great news. If the white smoke is coming from the engine running too lean this could be caused by several things including poor fuel injection pump calibration, clogged fuel filters (some people have 2 and dont realize it) and/or dirty fuel injectors. There is most likely some liquid you can add to your tank that wud clean the fuel injectors. You might also change you fuel filters and check you tank to see if it is filled with sludge and that is preventing the free flow of fuel. Good luck.

[haffiman37]

White smoke on small Volvos are usually a sign of the cooling system beginning to clog up. This usually starts in the exhaust bend.Water gets in, but not enough out to prevent it from vapourizing in the hot exhaust hose. If your engine is raw-water cooled:dismantle the bend, clean and check and run a cleaner in the whole system. Take out the draicocks at the bottom of each cylinder and flush it from there with fresh water.If you have a two-circuit system, cleaning the heatexchanger and exhaust bend is normally enough.DO NOT put waterpressure at your raw water pump as this may dislocate the seals and fill your engine with water!

[kcoffey]

Thanks, I''ll try the exhaust bend cleaning. I have a two-circuit system (coolant), and the heat exchanger was serviced by the Volvo guy before going in the water this season (gaskets had been leaking).