How fast does the oil dirty in your small engine.

[Gunatics_Adler]

Relating to my little Tecumseh powered snow blower in another thread.

I put Mobil 1 SL rated oil in it. Prior to this I ran it only once last year when I first got it. I think the previous owner rarely changed the oil cause I ran the snowblower for a couple hours and it was BLACK as heck. So I drained it and got a chance to use it again with our last midwest snow storm. I ran it for a couple hours to get us dug out over a period of three days and it is just jet black again. I am guessing that this just sludged up over the years and the new oil is slowly cleaning it out.

I ran out of my old Mobil 1 and put Rotella T 5w40 oil in it.

Am I wrong to assume that the motor was just dirty? Or do these really run that dirty not having air filters on them?

 

[Herz]

after I cut the grass once the 10-30 i use in my mowers get a bit dark.

 

[1999nick]

Originally Posted By: Gunatics_Adler
Relating to my little Tecumseh powered snow blower in another thread.

I put Mobil 1 SL rated oil in it. Prior to this I ran it only once last year when I first got it. I think the previous owner rarely changed the oil cause I ran the snowblower for a couple hours and it was BLACK as heck. So I drained it and got a chance to use it again with our last midwest snow storm. I ran it for a couple hours to get us dug out over a period of three days and it is just jet black again. I am guessing that this just sludged up over the years and the new oil is slowly cleaning it out.

I ran out of my old Mobil 1 and put Rotella T 5w40 oil in it.

Am I wrong to assume that the motor was just dirty? Or do these really run that dirty not having air filters on them?


I, too, use Mobil 1 in my OPE. In my lawnmower, equipped with the 160 GCV Honda OHC engine, purchased in 2000, I have used M1 5W30 SL until I ran out of my old stock about a year and a half ago. Since then, I have used M1 10W30 High Mileage oil, which is still SL.
I'm looking for their 5W30 High Mileage, but haven't seen it yet.

I have an hour meter on this mower, and it is used between 55 and 65 hours a year. It has about 525 hours on it now. At the end of a year's use, the oil still looks real good. Definitely not black. I always think about letting it go for one more year, but I always end up changing it. It has never been more than a sixteenth of an inch low on the dip stick in a year's time, which I attribute to checking the oil and wiping off the dipstick.

 

[ksJoe]

I changed the oil in my mower this afternoon, and it looked more or less like it did when I put it in last fall. A nice golden brown. I watched it poor out to see if there was any glittter and couldn't see any. There were some bubbles though because it was running immediately before I drained it.

The engine is two years old now, and I use pennzoil platinum 5w30 or 10/30 which ever I have laying around at the time.

 

[Gunatics_Adler]

Well I got this from my brother in law who has seized up several lawnmowers because he never checks oil. He gave me this blower after having to constantly have it worked on. He never drained the gas or put stabilizer in it so it gunked up the car every year. He went out and bought an attachment for his rider lawn mower and gave me his old "POS".

I am assuming it got junk oil and was rarely changed.

 

[boraticus]

Does the engine have any colour to the exhaust when running? There shouldn't be that much residual "sludge" in the engine to colour your oil that quickly. I suspect you might have soot from too rich a fuel/air mixture and not getting a clean burn. Soot accumulates on the cylinder walls and is washed down into the oil sump.

My diesel power plant will turn fresh clean oil to black oil in no time. Not that the oil colour really matters. The oil will retain it's lubrication qualities despite the soot.

 

[af0h]

Actually, a couple of hours run probably did it some good - considering how it was probably treated. Now, will it turn black that soon again? Maybe, maybe not. If it is in fact the Fuel/Air mix being to rich as boraticus mentioned, then it will probably do it again soon.

Either way, sure didn't hurt to put in a GOOD oil to help clean it out. Maybe a little MMO next time just for the heck of it (TCL and cleaning)...

The oil in my rider, tiller, push mower, and generator are all pretty clean looking by the end of the season, but I change them every fall anyway (usually with Rotella).

 

[Gunatics_Adler]

She is not running rich. The spark plug is a nice tan, but not black and fouled out. The exhaust does not smell of unburnt fuel as well.

I do not know how old this thing is, but from the look of it I would say 1980's. I know that Yardman does not even make Snowbirds anymore.

 

[dwendt44]

I use Mobil 1 0w30 in the snow blower(16 years old). It get dark by the spring but not black.
A couple of short interval oil changes should clean the insides up a bunch.

 

[Bror Jace]

Gunatics, I would say that it depends. The Honda (and probably Subaru/Robin engines) are very tight and the oil could stay clean for even a hundred or so hours.

The older B&S or Tecumseh engines were known to be kinda rough/crude and turn their oil black rather quickly.

From what you describe, I would say it is almost certain the new oil is cleaning old sludge/deposits from prior neglect ... Mobil 1 is good at this ... your Rotella even better.

If it is stored inside and started warm, I would use a conventional HDEO and change every 10-15 hours until the drained oil looks clean ... then switch to a synthetic and change once ever 25 hours or every season.

If stored cold, keep doing what you're doing. It may never get really clean but slowly dissolving sludge probably won't hurt anything over the life of the motor.

 

[boraticus]

If, after several flushes, the oil still turns black quickly, where is the coloration coming from? Other than soot from combustion, I can't think of another possible source.

 

[JTK]

Flat head / side valve engines will blacken the engine oil quicker than a comparable OHV engine. It's the nature of the beast. They run richer, less efficient and tend to have more blowby. My old Kohler K241 (10hp) turns Shell Rotella-T dark within an hour while my Command series V-twin 20hp takes 50+ hours to even discolor R-T.

Joel