White/light grey smoke out of exhaust from MD7A

[Nicks]

Hi guys,

Just noticed that a "fair" amount of white smoke comes out of the exhaust when running the engine.. Specially when giving it some throttle.. Anything to be worried about? As far as I recall, it didn't use to do that before.

[TeddyDiver]

Most propably unburned diesel. #1 check and chance the airfilter #2 injector leaking, check and change. #3 timing the fuel injection, repair or change necessary parts #4 not enough compression, rebuild the engine..
Good luck!

BR Teddy

[iancoombe]

White smoke sometimes indicates water from a blown head gasket, blue smoke is engine oil and black is fuel, although fuel oil with little compression could be blue.check your header tank for contamination and go through the tests that the previous poster suggested
Cheers

[Wotname]

Sometimes white smoke is merely condensed water caused by vey low air temperature...

[Shawn67]

With the smoke are you able to rev up fully in gear? I had an injector sticking part open and had lots of white smoke and could get up above 1400 rpm or so. I pulled the injector, opened it up and cleaned out the nozzle and it was fine after that.

For smaller amounts of white smoke it could be injector timing. Adjusting that can reduce/eliminate it. I had that as well after swapping out my injector pump.

Shawn


Sent from my iPhone using Cruisers Sailing Forum

[model 10]

Is it white or gray? White is water. Light gray could be unburned fuel. Stick your hand over the exhaust pipe and smell it. Big diesel smell, unburned fuel.

[DeepFrz]

Is the engine overheating? Could be steam if so.

[model 10]

Originally Posted by DeepFrz

Is the engine overheating? Could be steam if so.

How would steam get into the exhaust?

[Kenomac]

Check for the most obvious problem first, an impeller that has broken off a few rubber vanes and is now partially blocking up the water pump or heat exchanger. Causing the engine to run hot.

We just repaired this issue on a friend's boat yesterday. Repaired in on my own generator last month. Same symptoms, same cure.

Impellers only last 18 months to two years at most despite what the manufacturers claim, so now we change ours each year at the beginning of the season.

[Wotname]

Originally Posted by Guy

How would steam get into the exhaust?

Err… there is always steam in the exhaust although it rapidly becomes water vapour at the mixing elbow or water injection point.

[a64pilot]

Originally Posted by Guy

How would steam get into the exhaust?

Reduced raw water flow will do it. It's how I know I need to clean the strainer