Yanmar 3GM30 white smoke (help)

[SteveSadler]

My Yanmar did that too. I pulled the injectors to find black goo on them. After cleaning it ran clean. The carbon buildup was from running at low rpm and low loads where exaust temps don't get hot enough to burn it off. Volvo's manual recommends running it in gear full throttle for 20 minutes each time you run it. Personally, I'll just clean the injectors.

[Scubaseas]

Originally Posted by sinnerman

NOT recommended. It can damage the decompression levers/valves.

Find an injector shop near your home. Pull the injectors and bring them in for service.

They will test them, [cracking pressure and if they leak (dribble fuel) after firing], clean them and retest then. They may replace the nozzles assy. Probably cost you $250 for all three.

You will need the crush washers that go under the injectors (remove the old ones when you pull the injectors). The injector shop should supply new washers with the repaired units...

cheers.

This. Or do a diesel purge which is cleaning the injectors in situ with Liquimoly Diesel Purge but it's probable you have a bad srping or valve inside the injetcor itself that cleaning won't cure.

[Wotname]

Originally Posted by sinnerman

NOT recommended. It can damage the decompression levers/valves.

............

Would you are to cite the source of this statement or explain how such damage would occur?

Yanmar makes no such claim in their service and operation manuals and personal experience confirms no such damage occurs.

[seabreez]

Originally Posted by ShelleySailor

I got a 1997 Yanmar 3GM30F with about 1,400 hours in my Hunter 34. Lately the engine has been hard to start. When it starts it idles rough as if it is running on 2 cyclinders, the engine just shakes and vibrates a lot, if I push it to increase RPM after about 2-3 minutes it smooths out at same time when I crank it white smoke comes out of the exaust and it is smoke and not vapor. After it starts it has a lot of white smoke until I put it in gear and get going. Under load at 2300 RPMs it runs fine and the smoke goes away. I should add there is an oily sheen in the water when its blowing white smoke. If ran for 15-20 mins it will start right up and have no smoke and run fine for the rest of the day. Next morning it will do the same thing as before.
Any ideas?
Thanks in advance!

This looks very much like water in one or more cylinders. The first thing I would check is the oil... is it above the normal level? and is the color milky? or grayish color?. If so the next step is to remove the injectors and turn the motor over with the starter and see if you have water coming out of the injector hole. If there is water... a head gasket, or cracked head.

[ShelleySailor]

I have been reading a lot of forum posts and I think I may have hydrolocked my engine. before all of this happened I cranked my engine for quite a bit to get it started I did not know that I was suppose to close the water intake. I remember hearing a pop sound that did not sound healthy or normal and that is when I stopped trying. Later on a found a leaky fuel line and after replacing the fuel line and bleeding the air out of the line it started once again. BUT now now it starts with smoke, runs a bit rough for 5 minutes than I put it in gear and go and will run fine. The smoke goes away and runs smoothly.
although some sheen can be seen in the water so it may not be burning all the fuel?
Do you think this could be the result of hydrolock? or something else?

[skipperpete]

It could be the result of a hydrolock and the conrod would look like this photo of one from an overcranked 5 cylinder Kubota but it could just as easily be any of the other things suggested so far on the earlier posts. White smoke is most often raw poorly atomized fuel in the combustion chamber .... and it smells like raw fuel, no mistaking that smell ..... but it can also be from low compression/low heat. Precom chamber engines are well known for rough coldstarts and smoke, Caterpillar are legendary for the cold start rattle and smoke on the indirect injection models.

[Compass790]

It's possible you may have bent a push rod as well if in fact you did get water in the combustion chamber. A leakdown or compression test would be helpful if you suspect that. If you heard a sound you didnt like it's a good clue.
However I dont think this is as likely as you say it runs fine when warmed up but since you need to pull the injectors anyway you may as well perform the test IMO

[PaulvR]

Guys, am I wrong here....I was taught that under most circumstances.....

White smoke is water
Blue smoke is oil
black smoke is fuel

Also, why would an injectors performance improve with time?
But I can see an unhealthy slug of water at startup, until the fuel begins to flow 'over' the water trap..

[ShelleySailor]

So if there is a water trap, where is the water coming from? a crack engine block?

[PaulvR]

cracked block is possible, blown head gasket is possible....have you checked the water traps on your fuel filters?

[ShelleySailor]

I have replaced the filters primary and seconday about 2 weeks ago when I found the leaky diesel line which was the tube connecting the primary filter to the lifter pump, I did not see any indications that water was present in the filters so I don' think I have contaminated diesel (still possible but not likely) I will do an oil change tomorrow and analyze the old oil coming out for water.

[PaulvR]

Again, check the water trap on the bottom of the primary fuel filter, and take a sample from the bottom of the fuel tank at the pick-up.

Waiting to hear what you see in the engine oil..

[Compass790]

Originally Posted by PaulvR

Guys, am I wrong here....I was taught that under most circumstances.....

White smoke is water
Blue smoke is oil
black smoke is fuel

Also, why would an injectors performance improve with time?
But I can see an unhealthy slug of water at startup, until the fuel begins to flow 'over' the water trap..

You are not wrong but...White "smoke" can be completely unburnt atomised diesel. Watch a tired diesel on a cold morning at start up.
When the engine heats up the fuel starts to burn.
It may not be his problem but it's a possible scenario to be considered.

[ShelleySailor]

I replaced the oil today, I looked for signs of water in the old oil but did not see any. The oil was gray almost black but did not contain any water. I started the engine and she ran fine except for the white smoke for the first 10 mins and sheen on the water through the exhaust. I put it under load for 20 mins at 2000 RPMs and ran fine came up to temp and stayed at 180F

[Wotname]

Originally Posted by ShelleySailor

I replaced the oil today, I looked for signs of water in the old oil but did not see any. The oil was gray almost black but did not contain any water. I started the engine and she ran fine except for the white smoke for the first 10 mins and sheen on the water through the exhaust. I put it under load for 20 mins at 2000 RPMs and ran fine came up to temp and stayed at 180F

I wouldn't be so sure there wasn't water emulsified in the oil. Any hint of gray oil tends to be from small amounts of water emulsified in the oil. The more gray, the more water. It doesn't seperate out - well it might over few decades.