There's usually some unburnt mix in the muffler. If its working hard and getting hot it will burn some of this residue from inside the muffler.
I noticed today while in barn the jug with 24 on it in pics was 2.5gal. I didnt start using the 1gal jug for 24 till later. The 1gal jug has F on it still today too.
Apparently my wife checked the oil in the push mower before she used it last time (she likes to mow), and thought it was low, it wasn't, she checked it without tightening the dipstick. So she decided to add some, my last two bottles of Stihl hp ultra. Now it's Saturday morning and I've got plans for the saws, I've got no mix, no oil to make mix and my push mower is way over full of oilSo I'm off to the local hardware store and all they have, is these little packets of Oregon oil, 1.8 oz that says to mix with 1G of gas. The next store is at least another half hour drive, and I doubt they have any better options. Some quick mental math tells me that's somewhere around 70:1. So I grabbed two packets and added a gallon of gas.
Checked & added oil ? ? She's a keeper ! ! You have a teaching moment, tread lightly. Checking the oil, that has a lot of value ! ! Now get some oil & label it, lawn mower, mixed gas, car ... etc>>>>>>>
Yeah we had a chat everything is labelled now, was more my fault really. Those little tiny bottles were just too convenient, no funnel needed, and all the big bottles of oil clearly said motorcycle oil.
I'd be more worried that the mower burned nearly a qt of oil in a use! Had a push mower like that. Fill the gas and oil at the same time. Kept the bugs away haha!
The correct way to check oil on quite a few small engines that I have serviced, has been to check without turning in the dipstick. Just push down til it bottoms against the threads. What kind of mower is it?
My motorcycle is the same way, just bottom the threads, don't screw down. The manual for the mower didn't specify how to check, it's a craftsman. When I bought the mower it came with a bottle of oil to add that would fill it. I checked the oil after I added that bottle and it measured full when the dipstick was fully screwed down.
Most are a read by screwing the dipstick home, the exceptions being Kawasaki (they are always a no-turn, printed as such on the stick) and some other Japanese manufacturers. Everybody should check the engine manual for their equipment and make sure you know which way the mfg states the oil is to be checked. I like the old style push mowers, fill to overflowing, screw the cap in and go cut grass.
I was told the "don't screw it down" about 15 years ago by a shop teacher but I've yet to see a small engine that it said to do that in the book or on the dipstick. My lawnmower has a 25ish Hp Kawasaki, the cap just says "oil" I'm pretty sure.
Thats how I do 3of4 of my riders. The old IH is just push in no threads. The 3 push I dont remember off hand.
Checking the oil on my quad is a pain. Start and let idle for 5 minutes.....then off and let it sit for 3....then bottom the threads and check. If you check it cold you will easily overfill it by a quart. Damm hydro transmission making things complicated.
Sounds like a dry sump system. My KFX400 was the same procedure. damm thing would give you a heart attack if you checked it cold. (No oil on the stick)