Friend's PowerSmart lawn mower - never changed oil - blow by, flooded, won't run anymore

For mowers like this, I have found two types of oil to work wonders. Either things greatly improve or the fact that there is no longer TAR in the engine will allow a seriously worn engine to flow apart within only a few minutes.

For the more low-tech flathead engines that generally suggest 30W or 10W30, I have standardized on a Rotella T6 15W40 diesel rated oil. This has greater anti-wear additives and will not be of concern with fouling emissions equipment. Flathead or L head engines are more common on single cylinder push mowers but can be found in some older riders and other larger engine equipment as well. I had been using the Rotella T6 5W40 for a while on some of these and noticed more oil consumption and blowby as mentioned. Switching to 15W40 greatly helped with this. Most of this is run in higher temps outside as well so never sees winter use.

For engines used in the winter or OHV, I use the Rotella T6 5W40. Generally these specify 5W30 or 10W30 from the factory. Again, I have seen this work wonders or result in the fly apart of a seriously worn engine. It is either one or the other.

One success story with this was a rider with the Kohler Command commercial engine. It had been seriously neglected and the oil never changed. It would just blow smoke and bog down at the first hint of resistance/tall grass. I put the 5W40 in it and mowed once. By the end the mower was way up on power and no longer smoking. I drained it again, changed, and ran for an entire season before changing. The oil didn’t look bad even then. This also used hydraulic lifters which were super clattery at first. That problem also went away. I ran it for several years before the rest of the machine was pretty much falling apart and more of a pain than it was worth. I had been beating the crap out of it cutting brush and such once I had to start it with a battery right to the starter terminals. I sold it for $50 with a lot of other mowers and junk I was moving along for parts, scrap, or whatever.

Generators get 5W40 no matter the engine type as I figure they will be more of a winter item.

I never re-use oil with a few exceptions. I have used good used oil that I know doesn’t have contaminants to flush seriously neglected engines out. I run it 5 minutes, then drain. Another time I had a Kohler Courage engine on a rider. Then it decided to start acting up in several ways and one was burning about a quart of oil every 10 minutes of running. It would even start dieseling at times with flames out the exhaust from all the oil. It would run with the key off like this and even shutting down with the deck engaged wasn’t enough to get it to shut down at times. It would just keep running on all the oil it was burning. Starting it was hard and of course you had to walk away and let the smoke clear. Once it got running, the smoke turned to fire coming out the exhaust. It didn’t always do this with the deck engaged but once you disengaged, it would start to rev up and blow lots of fire at times. Again, this one got moved along after not too long.

@TheWonderful90s I thought about your statement that engines without oil filters to remove the particles last only half as long as engines with oil filters. Tom McCahill, in his book “What You Should Know About Cars” published in the early 1960s did not like detergent oil. He didn’t want the particles that detergent oil holds in suspension pumped through the engine bearings. He said that he preferred to have detergent in his bathtub but not in his crankcase.
The purpose of the filter is to remove these particles. McCahill claimed that the only reason for detergent oil was because some cars back in the day had hydraulic tappets. McCahill preferred solid valve lifters.
Thinking about small lawnmower engines with the valves in the block, I wonder if these engines might be better off with non detergent oil. If one changes the oil every 25 hours as specified in the manuals, maybe the non detergent oil would be fine. The particles would settle to the bottom of the engine and would drain out with the oil change.

Now this is a good point. For one thing I care more about the car than the lawn mower. I would rather experiment on something less valuable.

Say 5000 miles = 200 hours. The oil is good for 300 hours. I changed it after 200 hours but it has 100 hours of life in it. So the cost of buying oil for the car is 1.5x what it could be due to excessive oil changes.

The 100 hour remaining oil can be used in an engine that burns oil. The lawn mower is limited to 50 hours no matter what kind of oil is used because it lacks an oil filter. But it still benefits from having synthetic oil in it. The car should still benefit from having synthetic oil in it too.

The cost of oil for most of the air cooled engines is now free. The cost of topping off the oil in a car that burns oil is now free as well.

If all of the used oil gets used in something else, then I’m buying 3 units of oil for the car and 0 units for for the air cooled engines, instead of buying 2 units of oil for the car and 2 units of oil for all the air cooled engines. So the cost of oil is now 3/4.

Back to the original issue. I’m not surprised that a worn out mower with tons of blowby can’t mow grass. The engine is shot, it’s that simple. I doubt the blowby being routed to the carb has anything to do with it.

The only small engine I’ve had that used oil was one I bought that had already been around the block a few times and traded in. I had some blow by this year if you want to call pressurizing the crank case blow by. I took the breathers off and cleaned them but there is a very small hole behind the breather fir returning the oil to the crank case. These can get plugged up. I oroblem since cleaning them out.

City has small recycling drop off 4 blocks from my house. Takes waste oil. Cardboard. Cans. They closed last month. After 27 years. Said they couldn’t handle volume of cardboard. I blame Amazon. Have to go to big facility about 4 miles away. Been to my site probably twice a year for decades.

I am sorry to hear that you place closed down, now despirate prople will probably just dump it where ever it’s convenient and probably illegal and dangerous.

My county in Virginia runs a very effective recycling program, they would rather take care of the problem at the county level one big job at a time, than have people dumping chemical, oil, roof shingles, appliances, etc… off in fields, on the side or the road, or in the all the water that surrounds us. And not have to try to handle illegal and dangerous dumping all over the county…

We get two types of curbside pickups, one for normal house hold trash, dumped once a week and one for recyclable materials, glass, cardboard, picked up every other week.

If you have a lot to dump, you can bring it to the dump for personal dumping and that included almost everything, besides normal junk and trash, like chemicals, oil, roof shingles, appliances, etc…

The county also offers up to four-bulk pickups a year for up to three really large items like refrigerators, sofas, mattresses, etc…

And the county hold six bulk recyclings where you can bring in, again almost everything, including old TVs, computers, etc…

And when we have major storms they will even take cut up trees that are up to 8" in diameter and 10’ long…

And they collect the leaves from November through January…