L3800 white smoke on start up

[sburn518]

Rookie question, my new L3800, less than 20 hrs, puts out a small cloud of white smoke on start up. This only seems to happen when the tractor has been sitting a couple of days between uses. The tractor runs fine, has plenty of power, and does not do it if have to start back up the same day to do something else. Is this something to be concerned about and what would be the cause?

Thanks

 

[Bluegill]

Probably nothing to worry about, but mine doesn't do it. Maybe a little water in
the fuel? Bad fuel?

 

[CaveCreekRay]

Sburn,

My L3800 does the same thing and has since I bought it with 126 hours on the clock.

My brother thinks I have a leaky injector on one of the cylinders. Like yours, I see no smoke after the first start of the day. But, that first start creates a small puff of smoke.

Injectors are supposed to be open or closed, but not in between. Fuel injected cars maintain a high fuel pressure between starts. Diesels are similar. If one (or more) injectors is weeping a few drops into the cylinder between starts, that rich cylinder will smoke. The fact that is doesn't do it between starts as long as a couple hours tell me its a very slow leak or that if the engine is at all warm, the combustion is complete enough to start without a "puff."

I am taking my tractor in for warranty service next week and that is one of the things I want them to look at. I'll let you know what I find out.

I talked with the service writer at the dealership and he said a little start-up smoke is normal on Diesels. He suggested using the glo plug pre-heating but I tried it and it doesn't help. ("Hey! It's SUMMER in Phoenix!!!) Clearly too much fuel to burn off with the glo plug. But you wonder about many who experience no smoke at all. A friend in Ohio has a L3800 and tells me his starts clean too. There has to be a reason ours are smoking, and I think it has to do with a weepy injector. It only takes one. I don't seem to burn any oil between changes so the rings must be fine.

 

[CaveCreekRay]

Just doing some 'Net cruising and I Googled "Diesel smoke on start-up" and found this for Ford trucks:


Just went through this. PUll your injectors asap. Isn't a huge job and isn't difficult. You'll know by the time you finish if you have a bad injector. Replace the ORINGS while your at it. If you find an injector covered in carbon you have your culprit. The other thing you want to watch for is a cracked injector cup (what the injector sits in). See if you are getting fuel in your coolant.

The smoker replied:

That was the problem, found one injector with carbon, replace injectors and o rings and as you said smoke is gone. Thanks to both of you that answered.

Meethinks we have a weepy injector or two.

 

[sburn518]

Ray, thanks for the response, let me know what the dealer comes up with for sure.

 

[dmanlyr]

A slight puff or two of smoke is normal for ANY diesel engine. Most people when they report smoking is a CONTINUOUS cloud of smoke for some time, and that is a issue on any modern diesel.

My L3200 has given out a small puff for a split second on startup since new, and I doubt there is any issues with the injectors or anything else. The first couple of revolutions you are not going to get complete combustion on any diesel engine.

My BX25 did it, ALL of our fleet of boats and trucks (From 3/4 tons to class 8 rigs) do it, ALL of them. All of our other small diesel powered equipment does it as well. Hard to see sometimes depending upon the light and operator position, but it is there. Very normal, and not indicative of any issues. This is coming from a CAT and Volvo Certified diesel person!

In my opinion, those who report no puff on a cold start up are not looking hard enough, they are do it to some extent, try watching off the drivers seat. Nature of the beast so to speak.

Again I am talking a puff, not a continuous light or heavy smoking.

David

 

[Bluegill]

Our old L3750 puts out a nice big cloud of whitish smoke when first started.

Our L3800 puts out a small, almost unnoticeable puff of black smoke when starting cold.

 

[CaveCreekRay]

I agree with you guys... it seems like the nature of the beast. But.... so many people report clean start ups.

If the dealer doesn't find anything, I may pull the injectors and examine them. It runs just fine.

 

[CaveCreekRay]

OK...

Got it down to the service guy at my local dealer. Sharp guy. He agrees with whomever said, "If you don't have smoke, you aren't looking in the right place!" The smoke is a function of engine temp. Starting a warm engine will get you a clean start. Starting a cold engine, letting it run for 10 seconds (after smoke gone) and then stopping for 2 seconds, upon the second re-start, it will smoke again. You can do that over and over until, eventually the engine head warms up which helps complete the combustion.

He told me the Kubota fuel injection rack is unpressurized upon shutdown. So, there cannot be "weeping injectors" on this engine. I did a couple fuel filter changes on my German cars and the fuel line holds about 60psi fuel pressure after shutdown, for the next start. The Kubota Diesel evidently does not. That pressure is generated quickly upon cranking.

NEWSFLASH: Year 2 on your Kubota warranty is driveline only! I missed that somewhere...

I'll start a new thread for this: I have an alternator putting out 18v and I think the voltage regulator is toast. (My battery shows 14v unloaded) Normally, new alternators have the regulator built into the back of the alternator. The L3800 alternator is $280-$320, the higher being dealer pricing. Checking into the chance of getting the alternator re-built locally. Some Kubota alternators are on Amazon (!!!) and run $75 with free shipping. Not this one!

 

[dmanlyr]

Exactly what I posted..... a puff of smoke will happen on any cold start! Every diesel does it, nature of the beast.

David

 

[sburn518]

Guys thanks for all the info, I feel better now.