Because I have been doing it that way for 50 years ? Best thing I can come up with . No reason to change what's been working for me .Why would you store an engine with old oil?
It is said that the carburetor gaskets can dry out and become brittle.I gotta go with changing the dirty oil before letting it sit for the idle season.
I don't believe fresh oil sitting during said idle season will go bad.
ALSO (big one here) Seriously people, why do the Stabilizer route? EMPTY THE DARN FUEL TANK.
I'll tip and spill out excess fuel if need be but I leave enough to run down so it empties the tank and carb.
I'll add a drop or two of oil for obvious reasons.
Come Spring I add fresh fuel and pull the string....works!
At the risk of sounding rude.....Emptying the gas tank works so well. Why bother with stabilizers which cost money?
If I had a boat which had some difficult tank arrangement, maybe I could see "just pouring something in".
Take the smelly feet out of the shoes then put the shoes away.
You don't powder your filthy feet and put 'em back into the shoes for 6 months, do you?
I add 1oz of TCW-3 2-cycle oil to a 5 gal can of gas. This thin mix (640:1) is run in all my small engines. When I run the carb dry, it leaves a thin film of oil inside to prevent corrosion and helps keep gaskets from drying out.It is said that the carburetor gaskets can dry out and become brittle.
Always the end of the year for the reasons MRC01 has mentioned. Standard required maintain stuff from engine manufacturers too on ANY stored combustion engine ex. marine engines too.I am using a standard Toro home use walk behind mower in Michigan where it sits in storage 6 months a year. Is it better on engine life to change the oil at the beginning of the season or right before putting it in storage for the winter? It typically gets 15 hours of run time a year in the summer.
Make sure to run it for 10 min so it gets through the carburetor. I put Startron and Seafoam in the gas can right after filling it, so the gas I use always is treated.That's a good point. The OP didn't ask, but definitely mix Stabil into the gas at the end of the season. Gas can and will go stale over the winter season.
I change the oil late in the season. sometimes I have a few mows after I change it. I figure storing with fresh oil with a couple of mows on it is better than old oil with a whole season on it.My problem here is I don't know when it's the end of the mowing season. I'm usually still mowing in November, maybe even early December. And I usually get a first mow in before the end of January.
I don't think I'm doing any harm by letting the old oil sit "over the winter" as it's only a couple of months. I generally change it before the first mow of the year.
When I lived in a cold winter area it was pretty clear that when snow flew that the mowing season was over, and it was time to run the mower out of gas and change the oil. It's not so easy here.
I like to have fresh gas for the generator over the "winter" in case we have a storm induced power failure, so I generally empty the mower's gas can into the Honda and get fresh gas about the end of mowing season. And as it only sits a few months I don't put anything in it.
I think it would be hard to verify much difference in engines that are serviced annually with quality oil.Does anybody have verifiable proof of one method over the other ?
^This is my approach (or, at least it was, prior to moving to my current home where I use the mower to mulch leaves/needles/sticks all year - GD pine and sweetgums!)I gotta go with changing the dirty oil before letting it sit for the idle season.
I don't believe fresh oil sitting during said idle season will go bad.
ALSO (big one here) Seriously people, why do the Stabilizer route? EMPTY THE DARN FUEL TANK.
I'll tip and spill out excess fuel if need be but I leave enough to run down so it empties the tank and carb.
I'll add a drop or two of oil for obvious reasons.
Come Spring I add fresh fuel and pull the string....works!
At the risk of sounding rude.....Emptying the gas tank works so well. Why bother with stabilizers which cost money?
If I had a boat which had some difficult tank arrangement, maybe I could see "just pouring something in".
Take the smelly feet out of the shoes then put the shoes away.
You don't powder your filthy feet and put 'em back into the shoes for 6 months, do you?