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

Would bog down he cut tall grass. Became very difficult to restart.

Had to remove the air filter to get it started. Doing that exposes the crank vent to the air. Changed the oil with some used 5000 mile synthetic from my car. Old stuff was not even quite black but almost grey like aluminum. New used stuff looks almost like the old stuff after a half hour running. It’s a bad sign when new oil is black right away.

Once started it would sometimes stall while putting out a huge amount of white smoke after a bit of heavy cutting or going up a hill. The oil separator must be bad on not able to handle so much blow by.

The issue was there is so much blow by that the fuel air mixture getting in to the crank case goes out the crank vent and in through the carburetor again where more fuel is mixed in, resulting in a too rich mixture.

Took forever to figure this out. I even ordered a new coil for it. Directed the crank vent to the outside now it starts fine. But if I start it with full oil it loses 1/4 of the oil out the crank vent aftel a half hour of mowing.

I guess it’s time for a new mower. The nice thing about 2 stroke is it either always had clean oil in it or someone forgot and it’s blown up all the way.

Anyone have stories about very worn cars or other engines? I don’t think cars vent the crank case through the carburetor again like this did.

It’s a two-stroke engine push mower and not a four stroke engine???

And since when do you run anything but 30W or maybe 10W30 weight oil in a lawn mower???

And why are y’all so freaking cheap that you are going to put in dirty used oil instead of fresh clean NEW oil in an engine that already has a running issue, how much oil can a small push mower or even a riding mower take???

It sounds to me like you may have caused even more damage to the engine…

Try putting the correct weight NEW oil in it and see of that helps… IF it call for or has been running reg 30W oil and it already has oil ring sealing issues, then your full Synthetic very low weight oil (5W20, 0W20) is going to be like water inside that little engine… No wonder it has SO MUCH BLOW BY…

And every 4 stroke push mower or reg riding mower for that matter (that I have ever used or seen someone use) bogs down when you try cutting tall grass, a 2 stroke has even less torque, so will bog even more… And they normally smoke a little when being bogged down…

Maybe I am missing something here and these new fangled mowers that are being made in the last few years to make all the tree huggers happy are all running on used full synthetic low weight (thin) oil… But who knows?.?.?..
Or maybe with neighbors like you that work on other peoples ICE lawn mowers, it would be better to go with a new EV mower anyway…

All just my opinion and others will probably differ greatly… :wink:

It’s 4 stroke. Just sayin that 2 stroke is better for people who never change the oil in their stuff.

A few quarts of oil are probaly worth more than the whole mower at this point. 10W30 drained from my properly maintained car is free!

By mowing the lawn a few more times this summer and me not insisting on him changing the oil.

It would run rich due to the fuel air recirculation problem and lose a lot of power. After filling up the oil it would splatter oil in to the intake and it made more smoke than one of those small smoke bombs that you get to celebrate Independence Day! It actually was nice given the mosquito situation.

I just got rid of a lawnmower I purchased in the spring of 1992. The manual for the motor specified 30 weight high detergent oil which I used. Three years ago the engine was burning oil and putting out blue smoke. I changed the oil at the beginning of the season and poured in full synthetic 10W-30 oil. It cut the oil consumption by 75% . The fix lasted three seasons until the engine again began putting out the blue smoke and the oil consumption went up.
The handle broke on the mower several years ago and a new handle wasn’t available. I repaired the handle with electrical conduit. I replaced the mower this season with a battery powered mower. I don’t have to worry about oil or gasoline and I can mow my entire yard on half charge.

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A few years ago Briggs and Stratton changed their oil recommendations to enable 5-30 synthetic year round instead of 30 wt depending on the season. So I now use this in my mower, snow blower, generator, and pressure washer. No problems.

And just to add, their new no oil change engines rely on continually adding new oil until the thing wears out. The engines are not much different than the old ones. Regardless, for 20 ounces of new oil to change, I just can’t bring myself to do this. Climatistas and guys that don’t know how to change oil might do things differently. Of course they rate their engines at 200 hours before they fall apart.

Coincidentally, that’s the same year I purchased my 4-stroke Sears lawnmower w/ 5 hp Tecumseh engine. Still working, starts on first pull. Hasn’t had a lot of hours of use, maybe 15 minutes a week. I’ve had to rejig the carb over the years, so instead of pushing on that black rubber bulb, now I use a bicycle pump to prime the carb for a cold start. And the fuel inlet at the carb leaks, so I have to clamp the fuel hose coming out of the gas tank with a hemostat when not in use … lol …

Sounds like it was over heating due to built up grass in the cooling passages. The synthetic handles the higher temperature better. This is now very common since the rotating screen filter has been done away with on most engines.

I blew out the fins and cleaned the screen at the end of the season and at mid season.
I think the rings were worn. The compression seemed low when I pulled the starter cord. I think I got my money out of the mower. I have always maintained my equipment.

My mower is a 2017 Toro personal Pace, 22" Recycler Lawn Mower. It is one of those “never change the oil” types… It came with a 20-ounce bottle of 30W oil. The instruction manual says to put in 18-ounces, which I read after dumping the whole 20-ounce bottle in, but 'lo 'n behold, the oil came right up to the fill line on the dip stick. After running the mower and then letting it cool down, the dipstick was only about 1/8" down from the top level…

I mow the grass about once a week and it takes about 2-hours. So it gets about 25-hours of running time every 3-months. I change the oil in my mower by running it for 5-minutes for so and then I tip on its side and drain the oil out the fill spout. Since I know it will hold 20-ounces, that’s what goes back in.

I’ve had to replace the rear wheels and the drive gear in each wheel once and the mower still starts with one pull… It cost just over $300 from Home Depot when new, and they sell its replacement for just under $500, so I plan on take care of mine…

The personal pace feature means it self-propels itself at my walking speed, from creeping up to about 4+ MPH (a fast walk…). The handle slides up and down, and as you walk forward, you depress the handle and it pulls a cable that tightens the drive belt and that belt rides on variable pitch pulleys that drive it faster or slower…

My neighbor has a Honda Mower that is sooooo quiet, it could pass for electric, but it has only one speed in self-propelled…

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Yeah I get the newer stuff is using lighter weight oils now, but how many recommend using USED OIL??? And I doubt that the mower in the OP is that new or it wouldn’t be that worn out…

On a HP (race) engine the thinner the oil the less friction, the more HP it makes up until it is no longer thick enough to seal the piston rings, so to thin of oil will reduce the sealing of the rings resulting in a loss of compression and more blow-by, and a loss in HP, you have to have the right oil for the combination and fuel being used… A top fuel engine that produces way over a 1,500 HP per cylinder, are somewhere in the 15,000 to 20,000 HP range at this time on a 500ci V8 and it runs a 70 weight oil NOT a thin oil due to being able to seal the rings because of fuel wash down…

In simple terms, the more fuel the engine consumes per cycle, the more oil needs to be retained in the valleys (think honing) on the cylinder wall, because the piston ring is a lubricated component, and proper lubrication is about having the right oil (type and viscosity) in the right place, at the right time, and in the right amount. It is the oil retained on the cylinder wall that lubricates the ring and also seals.

Fuel dilutes the oil, which can wash the oil off the cylinder walls. When that happens, bad things occur, namely increased blow-by and ring wear. Accordingly, more valley depth (remember honing) is needed from the cylinder-bore finish to retain oil when higher levels of fuel are being consumed. For example, a 410ci, methanol-injected engine needs a deeper RVK (valley depth) than a gasoline-fueled EFI engine, since an injected methanol engine typically runs twice as much fuel than the EFI gasoline engine. As such, deeper valleys are required to retain more oil to offset the increased fuel wash…

One reason EFI engines last 200,000 miles without a rebuild or “ring job” and more miles now a days, compared to the early days of carbureted engines that ran rich at start up to warm the engine as the access fuel would wash the cylinder walls down causing damage/ware to the cylinder wall(s) and piston rings and therefore smoking bad around 100,000 miles and needing to be re-ringed/rebuilt…

I bought a toro rear bagger self propelled around 1985. I was so sick and tired of trying to start my old dynamark, I told the guy I wanted electric start. Naw he sai this is a gts, guaranteed to start on the first or second pull. Danged if he wasn’t right. Suzuki engine and an absolutely solid machine. I used it till a bigger yard in 94 when I went with a rider. Gave it to the kid to use and got it back. I finally gave it to a local small engine shop. Hated to get rid of it. Special service guy in nam and now lives the quiet life.

Sure about that ? I thought it just lets the belt slip if you are walking below full speed.

On a Personal Pace from 2016 the bearings in the drive shaft would wear out and then the gears inside the wheels would strip the wheel gear teeth. An updated bearing that is better sealed was released. Had to replace the belt in it too. And the end of one of the control cables on the handle broke off. Carburetor bowl is all plastic. The drain is a 1/4 allen wrench now. The mower wasn’t too bad. Not impressed with the grass build up in the engine or the never change the oil thing.

My free powermore powered snowblower works ok. Oil is clean as heck. I did change carb a few years ago. It was $14 online. Recoil broke so I had to use elec start for awhile. Then I got a new recoil. That cost more then carb.

Am I sure of it? No, not now, after reading your post, I turned the mower over and I hit YouTube and I think you are right, it works on a “limited slip” principal… As I wrote, my mower has been very dependable and I think, maybe I was thinking of my grandkid’s moped… It was a Gillera Moped and it had a belt drive and the engine centrifugal clutch assembly that not only engaged the drive, it changed the pitch of the pulley, the faster it turned, the more it pushed the belt out, sort of creating a “larger diameter” pulley…

As for Grass build up, mine is horrible when the grass is damp, I keep an old putty knife next to the mower’s “parking space” and I clean out any build up and I do not put it away wet. We keep the mower in the garage and if it’s put away wet, the grass start fermenting, and the garage smell like a horse stable (that is not properly cared for…). I grew up with horses and the aroma of horse hockey is (like the words of Colonel Sherman Potter in the “MASH” TV series, when he stepped in the “hockey,” is like a tiptoe through the tulips…).

This fall, I will probably have to bust her down and replace those axle bearings, the drive gears and wheels and the belt…

I’m going to do something I rarely do and that is name calling. Looks like most of you guys are elitist snobs when it comes to oil. I have reused not quite used up oil a lot over the years in old engines that consume a lot of oil, cars and lawn mowers and I just consider it environmentally sound.

Anytime I do an oil change on a vehicle that has less then 6k on the oil, I pour the used oil back in the bottles and save it. I had an old Toyota that consumed a quart every 500 miles that I used it in, still did regular oil changes every 4k with new oil and filter, but used the saved oil as makeup oil. I still have an old riding mower that I bought in 97 and used it up till this spring when I got a new one.

I hadn’t changed the oil in it since 2011 and probably didn’t do more than 7 or 8 oil changes in its lifetime. I have used the used oil as makeup oil ever since it started burning oil. It would consume about a quarter of a quart every mowing session, about two hours +/-. The deck was cracked and no longer useable so I took it off but still use the tractor to pull my trailer around the yard collecting broken branches and other yard debris to haul to the dump. I have a ball hitch on the back of the tractor. BTW it was a Murrey 52" lawn tractor bought from Walmart. The new rider is a zero turn and towing is not recommended.

I can’t see throwing away oil that still has some life left in it and then burning brand new fresh oil. I’d rather burn up the oil that was going to go to recycling.


I’ll wear the label of elitist oil snob with honor. I’ve had and cared for engines of all kinds since I was 10 years old. I respect machines and the people that make them. When I traded my Buick in with 520,000 miles and no oil usage, the salesman wanted to know how often I changed oil. I said every 3000 miles without fail. He slapped his knee and said I knew it. My first oil change was in 1958 with dad talking about the importance of changing oil. I don’t understand how someone can have a piece of machinery that burns oil unless they bought it that way, and then why would they buy it. It’s just a matter of satisfaction in caring for a piece of equipment. I’ve got prolly 10 gallons of used oil waiting to go for recycling. If someone asked to have it to put in their engine, I wouldn’t give it to them. I guess I’m just a hopeless deplorable who waxes his lawn mower and washer and dryer and vacuum cleaner too.

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If I notice the oil drained out of a car engine still looks pretty clean, I’ll put it in a big bottle & use it for general oiling use, garden tools, rust-repelling, door hinges and the like. That’s an infrequent occurrence though, the oil that comes out of my vehicle engines usually looks like it was well-used & ready to come out.

I do a slight variation on that. Instead of good used oil, I have a bottle and funnel set up in my shed. When I empty a new bottle of oil into an engine, I take the “empty” oil bottle and invert it into the funnel. Each bottle of oil will drain another tablespoon of oil over the next few hours. After I accumulate some oil, I put it into my squirt can and use it for general oiling.


The oil life of an engine which has no oil filter is about half that of one that does. It doesn’t matter if you use expensive synthetic oil since there is no filter to remove particles.

Using filtered expensive used synthetic 10W30 oil from the car at 5000 miles may actually better for an air cooled engine than using new 10W30. Non synthetic oil can’t handle the heat as well.

Nearly 100% of cars on the road now are using used oil. After the first trip the oil becomes used!!! Only 2 strokes and other engines which use consumable oil can get around this fact!

Good point, now next time you do an oil change on your Lexus put your time before 5,000 mile used oil back in your vehicle instead of new oil… Tell me how that works/worked out for ya in a few years…
If not then tell me why you replaced it (your oil) in the 1st place if you are so confident in how good it still is after 5,000 miles, as a matter of fact why even change it if oil does not break down over time and use, never changing your oil would help the environment out a lot…