White Smoke on Startup

Barnacle Bill · Jul 30, 2013

One reason for white smoke upon start up is water getting in from the engine cooling area to the cylinders and it goes out the exhaust in the form of steam. This usually is because of a bad head gasket, warped head, etc. Might not be your problem, but might be too.

Snotter · Jul 30, 2013

My perkins doesn't have glow plugs. I've never had to give it throttle to start it. However, the engine does get used regularly.

Tim R. · Jul 30, 2013

Agreed. Not normal. PO was misinformed or lying. Did this not show up on the sea trial?

richk · Jul 30, 2013

Sorry but I don't have the time to prepare a thorough response but I can say that I suspect you have a 3GM30F, which I do as well on my H35. I really don't remember if it's related but I replaced my injectors myself....if that's the problem. Only cost was injectors and it was an easy (for me) job and I am not mechanically inclined...just ask my sons!

Benny17441 · Jul 30, 2013

No it is not normal but it is a true and tried method to start an engine that may have lost some compression due to wear. In the absence of a glow plug, compression is what heats the diesel fuel to ignition temperature. Compression is usually built up in a handful of revolutions to its max but in a worn engine a quicker cranking sequence is required to provide more revolutions and that is accomplished by increasing the throtle. The white smoke is just the burning of the excess diesel fuel that was pumped into the cylinders during the cranking sequence. When talking about compression I like to talk about oil grades. A good indicator for the condition of the engine is how thick the oil may be. A thicker oil may disguise the loss of compression in a worn engine while a thinner oil may cause a fairly good engine to smoke some. Another thing to take into consideration is ambient and water temperatures. It is harder to crank an engine in cold weather as the oil acts thicker and it takes longer to reach fuel ignition temperature. Even a good engine can benefit from cracking the throtle at startup in cold weather. Batteries are weaker and there is more friction in the engine so you will need more revolutions quicker. I could not help notice that it may get kind of cold in your part of the world. If once it starts the engine runs good and does not burn oil I would not worry to much about it as probably has many years ahead of it. If on the contrary it runs rough, lacks power and burns oil then it might be in need of a partial or complete rebuild.

kloudie1 · Jul 30, 2013

Doug, I suspect you have a 3GMF like the one in my 34. Have you tried starting it with the throttle just cracked a little? I've never heard the "full throttle" story for starting.. Here, the temperature is rarely below about 50 F in the boat, but the engine always starts by the second or third revolution and many times it will start on the first cylinder to come to compression...

NYSail · Jul 30, 2013

Maybe I didn't read it but have you tried starting the engine Normally to see what happens? I to. Have a yanmar.... I push the throttle up about half way then back to idle and then start . No white smoke

Don Crowther · Jul 30, 2013

I use about 1/4 to 1/3 throttle for start. No smoke. I would give that a try before digging to deep. It could very well be low compression on one or all cylinders. If it still smokes maybe time for a friend or mechanic to look at it.
Good luck.

victorhoisington · Jul 30, 2013

I have a 2GM20 which puts out a mix of white/black smoke, usually the black is if I try to over rev when starting. Before my latest fix, when I started the engine, I would have to crank it a while, push the throttle to full open crank some more and finally it would catch on 1 cylinder. After loping along for a few cycles, the 2nd cylinder would fire and she pured like a kitten. Until then I got lots of smoke, etc.

PO always had these problems gettig the engine to start, Over a period of a couple of seasons I treated the fuel, fixed the water pump and this season finally solved the starting problem, the fuel lift pump was leaking. I noticed a slight drip at this pump which turned out to be the fuel lift pump. After tightening the 4 screws on this pump the engine starts almost immediately and complains if I provide too much fuel too soon.

I think I'm still starting on only 1 cylinder and so still have some work to do but, its nice not having to crank too much.

Check all fittings in the fuel delivery system from fuel tank to injectors and back. Make sure everyone is tight and not leaking (or seeping). Air in the system even the smallest amount may be a source for your problem.

I'm no diesel mechanic so this may not be a true source of the problem but, the more I learn about these engines the simpler they are. Fuel, compression and air and they fire every time. If they don't start immediately something is wrong.

Good luck and I look forward to others with more knowledge.

Victor

Bill Roosa · Jul 30, 2013

the white smoke is normal if you are using full throttle to start. It is the unburned fuel from the few strokes that did not get hot enough to ignite. the issue is that either the cranking is not fast enough or the compression is lower than normal.
Does it crank OK, ie at a normal speed? does it do this after it is warm?
if the crank speed seems ok then I'd do a compression test and see what that revels. if the crank speed is not ok then check all the high current connections. if they check out pull the starter and test the commutator for a short across on set of coils.

jviss · Jul 30, 2013

I hate when people say "throttle" when talking about diesel engines. Of course, there is no throttle, there's a speed control.

This comment is particularly bothersome:

Benny17441 said:
...a quicker cranking sequence is required to provide more revolutions and that is accomplished by increasing the throtle.

How?

DougM · Jul 31, 2013

White smoke equals water, could be a head gasket, or worse, a cracked block. Look at the crankcase oil, if it appears milky, that could be a cause. Since oil floats on water, if you could get at the drain plug, you could open it to see if water comes out first.

As far as starting, the most I have ever had to do is open the throttle slightly, and the engine will start in just a couple of revolutions, even after setting all winter (Yanmar 2GM20F).

jviss · Jul 31, 2013

DougM said:
White smoke equals water

Not always. Can also be fuel. White smoke that goes up is likely steam, though.

WayneH · Aug 4, 2013

Sounds like you've got the answer.

YVRguy said:
- If I've had the engine running for a while it will start with no throttle and no smoke after that. Even after being stopped for a few hours.

You might try a "hot" start next time just to see if you REALLY need to start with full throttle. Yeah, I know "throttle" is not the right term but it works.

Chris Patterson · Aug 4, 2013

Uh, if not throttle, then what WOULD it be? It's not gas pedal. Or an A.F.U. like on a plane. Certainly nothing artificial about mine..

jviss · Aug 9, 2013

Chris Patterson said:
Uh, if not throttle, then what WOULD it be? It's not gas pedal. Or an A.F.U. like on a plane. Certainly nothing artificial about mine..

I know this thread has gone cold, but this terminology intrigues me.

A throttle is a device to choke off the air flow to an engine. In gas engines this also reduces the fuel flow, usually because the carb is a Venturi device.

On a diesel your speed control in the cockpit is controlling the speed setting of the governor, and the governor controls fuel delivery to keep the engine speed in regulation. Thus, no throttle.

Ross · Aug 9, 2013

cold weather starting on construction equipment makes lots of white smoke until the engine gets hot. My little Volvo blows a cloud of black smoke on a cold start at full throttle and will start on the second turn, at idle, in gear, on a hot start.

Chris Patterson · Aug 9, 2013

throttles.

Actually, my question was genuine, and now I'm thinking it was misconstrued as sarcasm. I suppose that's an easy enough assumption, bearing in mind who said it. But I don't think I've ever heard it called anything else but throttle, and in the definition it seems like the term may be slang. Interesting.
And an old dog DOES learn a thing now and then..

And one more thought, I've dealt with countless numbers of diesels in my life, and any kind of smoke at start up has never alarmed me. I'm not saying it should, but I've seen a thousand of them that did. It's what they do when it gets warm that I'm making a life decision on. Its life..