I heard from an engineer friend that it isn't just metal in there. Moisture and carbon from the cylinder gets deposited in the oil as well.

On another note, I also read for generator engines, that its good to run until hot so it can burn off moisture and other stuff that's created during a cold start.

My mower has black oil and I change it twice yearly.

I would consider black oil on a 2 hour old engine to be abnormal.
However, I wouldn't get concerned until I saw the color of the oil on the next change, assuming you are using a decent quality oil.

I would be alarmed. What oil did you put in it when new? Is your air filter in place and installed correctly? Does the exhaust contain black smoke at any time? Does it use a lot of gas? Most of the time I can go all summer on the 10684 and the oil is still so transparent it's hard to see on the stick. Something is definitely wrong.

Well, I put in the oil that came with the mower, a 20 oz bottle of Lawn Boy oil. My air filter is installed correctly, I just checked it. And the exhaust is perfectly clean. I don't think it's using excessive amounts of gas, 15 minutes of mowing at a time and I have to fill it up about every 4 times.

Was it 2 stroke oil?

I'm quite sure it wasn't 2 stroke oil, but I threw the bottle away a little while ago, so no way to verify. My attention to detail is usually pretty good, and I bought the new bottle based on the specs on the first bottle, so I'm quite confident it's 4 stroke.

Thanks guys for the quick replies guys. The oil was most definitely the same as the link you provided saxman, and the oil I put in is some stuff that I got from Canadian Tire, SAE 30, gauranteed to meet or exceed Tecumseh specifications.

Oil after 2 hours of use should look like new. Are you sure the mower is running smooth and is it auto choke or does it have a primer bulb. I found the the new B&S engines with auto choke run very rich. You have a major problem. You better get it fixed. I have seen mowers that have run for an entire season and the oil still looks like new.

The mower is running perfectly smooth, and starts with one pull every time. It doesn't have an auto choke, it does have a primer bulb. The engine is a Tecumseh LV195EA. This has got me a little worried. Maybe I will cut with it a few more times and then change the oil again, see if it looks better.

One would think that the blackness is caused by excess emissions -which why some comments went towards excess fuel. It may simply be that the engine needs more running time and maybe an extended running time at that. Mow that neighbors yard the next couple of times as well and get it the operating temp up there. I have noticed also that some trade store small engine oils have that strange blueish sheen when out of the bottle. Maybe use a regular automotive oil as pointed out earlier. But really, what would one change if the engine produces black oil soon anyways? If the carb is working as it should, and oil consumption is nil no harm done and nothing that would be a valid warranty concern that I can think of.

You cannot blow this off as a 'normal' abberation. Black oil in this case probably indicates excessive blow-by resulting from missing, broken or improperly-installed piston rings. I believe you should take it back for an exchange. No healthy LV195 is going to blacken the oil in less than 50 hours or more of hard use. You have a major problem.

Update: I just called Lawn Boy regarding this issue and they said that they are not at all suprised that the oil was black, and that it is part of the normal engine break in-first oil change routine :)

I'm somewhat skepitcal, but I'll take their word for it and change the oil again after a few hours of run time.

tomplum, I actually noticed that the Lawn Boy oil that came with the mower had that blueish tint to it when I put it in the mower, the stuff that I got from Canadian Tire didn't.

Best I can say is monitor the oil level closely- noting any changes up or down in level(check while cold), plus extend the run time. Could the specific blend of an oil create more "blackness"? Every once in a while, someone will hand me a bottle of store brand oil and it seems to have that tint. What additive may create that, I dunno. Maybe the Lawnboy blend created the darker color. Did they put something in to aid break in? Got me. It will be interesting to see what the next change brings. If it doesn't run rich and doesn't consume oil, personally I wouldn't lose sleep over it. Document your communication w/ Tec and LB. Save oil samples if you wish.

When 'judge' says 'black', I'm assuming black, opaque oil, like black ink. No transparency. This is how oil gets in an engine with bad rings. Brown with transparency could be normal after 25 hours but not after two hours in a new engine. I leave my Opti-4 SAE 30 in my LV195 for two years and it's still hard to judge the level on the stick. Again, this is a problem IF IT IS INDEED BLACK.

The oil definitely was black and not brown. I wouldn't say that it had no transparency like ink, but it was dark enouch for me to notice that something was odd.

Anyways, thanks everyone for the help. I'll wait it out for one more change here and see where things are at.

I'll update the post when I do, if you guys would be interested.

Cheers.

judge dredd:

I've not joined in, but have followed your thread with much interest. Having had many years experience with small engines, I must say I've never heard of a situation/condition such as you describe. I agree with saxman....something is quite wrong here. Some possible answers have been offered, but this is an extreme condition and none of the answers fit what you're describing (IMHO). You've had some very knowledgeable guys attempting to help, and yet no joy.

Count me as one who would appreciate a follow-up from you. I hate a mystery without a conclusion! ~smile~

Hal in PA

Well, I said I would post an update and here it is.

I just did the final mowing of my grass and did the end of the year maintenance stuff. Changed the oil, removed the spark plug and put 1oz of oil in the combustion chamber, and let it run dry out of gas.

Now to the point. The oil was dark again. Not nearly as bad as the first time I changed the oil, but definitely not the golden color that it is when it goes in. I might call Lawn Boy again, but I suspect that they will say it's normal. Apart from that issue, the mower runs great. Always starts with one pull and sips gas pretty conservatively.

Cheers.

All's well that ends well. I'm still stumped, never having seen this before. How about this possibility - 2-cycle oil in the 4-cycle bottle? 'Bluish tint'?

The oil I drained out of my Sers Craftsman tractor had a greenish tint. It has the 18 horse Briggs & Stratton engine. I put in Quaker State 5W30. The oil that came out of it was fairly black other than the greenish tint. Just keep and eye on it.

judge dredd; In re-reading your last post, you seem to be saying that after a season of use, the oil was dark, but not black like before. This would be as-expected for any good oil. When I replied that I was 'still stumped', I was referring to the original 'black oil' incident.

I change the oil used it one hour now it's black

Interesting. Some oils made with lots of detergents turn black quickly. Many small engines specify non-detergent oil which does not color up. I would change brand of motor oil to see if it makes a difference.

What is this on 349?

Yes , detergent oils will definitely discolour quickly and cause darker oil as it removes carbon from the rings . It can also cause foaming in a splash oil system , which is why it is not recommended in many mower engines . Have not seen oil turn black in a new mower in 2 hours of service ?

All oil is now 'detergent' and has been for the last 70 years. You can still get 'non-detergent' for car engines with Babbit bearings. but you won't find any non-detergent oil on the shelf at Walmart. One of my mowers is 17 years old and the other is 13 years old. The 17 yr old is a Lawn Boy with Tecumseh 195 and the 13 yr old is another Lawn Boy with Honda 190. I can run them for two years without changing oil and its still so clear I can hardly see it on the stick. Something is very wrong with either the oil or the mower in the subject post. Maybe it doesn't have an air filter on it.

Sax all my splash system push mowers run straight 30 non detergent . Briggs still advises against detergent oil , so does Kohler. I have always used Valvoline or Rotella T-30 . Briggs Sae.30 is over priced . In my Zero turn or Comercial Toro with the 180 Kai I run Synthetic Amsoil 10-30 since it has a pressurized oil system & a auto style spin on oil filter . I have had more than one dealer advise that they would not warrant detergent oil usage in any splash system mower engine . I do agree that black oil in 2 hour usage is highly irregular . Even running without a filter would be pushing the envelope unless the ambient conditions were extremely dusty , I would have thought over rich fuel lol. Anyhow he never advised of his final outcome , so I guess his black oil never caused any mechanical difficulties !