5W20 oil viscosity issue

Why use a storage oil that is different than what you normally run?
Sometimes, I need to run some of my summer equipment in the dead of winter to move it around or do some short term task. 30W oil is pretty thick and I’m not going to be running it for long. The 5W30 is a decent compromise under those conditions and I have boatloads of it around anyway.

In fall I drain all my OB lower units to get the water and oil out of them. Then I fill them with generic machine oil for the winter in case they get water intrusion. I drain that out in the spring and put in the recommended gear oil. No sense wasting good gear oil :wink:

Depending on the temp small engines generally take 10w30 in cold weather and 30 wt in warm weather. Thus you have to change oil twice if they are going to be used or started year round. I had 3 hours on my lawn tractor over the winter and had to change oil for the summer.

It seems to me if a small air cooled equipment engine is not going to be run in the winter, then all is o.k. if the engine is stored with 30 weight oil and fuel stabilizer in the gas tank. At the end of the season, I put fresh 30 weight in my lawnmower, change the air filter, add fuel stabilizer to the gas tank and fill it to the brim, remove the spark plug and squirt some oil in the cylinder and then turn the engine over a couple of times stopping when compression indicates both valves are closed, sharpen and reinstall the blade and put it away. In the spring, I remove the spark plug and turn the engine over, put in a new plug and start the engine. I’ve always had it start on the first or second pull of the starter cord.
If an engine is stored in a building where the temperature is above freezing and needs to be started, I see no problem with using straight 30 weight oil. If the engine is stored in an unheated building where the temperature drops below freezing, then I would use a multi-viscosity (5W-30) synthetic oil. Guidelines for small engines used to say to change the oil after every 20 hours except under dusty conditions. These guidelines now say 50 hours. I usually change the oil mid-season and this works for me. Single viscosity 30 weight does the job for me.


These guidelines now say 50 hours.

Then lucky me. 10 mows/yr @15min each =2.5 hours/yr. Gives me 20 years before I need to change oil into the make work machine. To think that I already changed oil once in this 2nd hand (I’ve had this unit for 5 years) mower makes me a little irritated/

I have never even bothered using a gas stabilizer. I just let my small engines run fairly low or out of gas, then take my chances. Once it warms up, I change the oil, fill with gas, and go. My mower and trimmer both started on the 2nd pull this year, and I’ve never had any problems from this. When the temps get cold, gas is less volatile, and if the cap is on the gas tank nice and tight, you shouldn’t have any real problem. I’d make an exception for 2-cycle engines–I’d make sure you run the tank dry before storing or the oil can settle into sticky goo in your fuel system.

You’re probably doing more harm than good with multiple cold starts on engines with splash lubrication in bitterly cold weather.