All gassed up and ready to go
Gardeners use lots of power equipment to help them with their work.
A quick look around the garage or tool shed reveals tillers, leaf blowers, mowers, string trimmers, chain saws, pressure washers and more. In the past, you just went down to the gas station and filled a can, put in some oil for some and that was that. Not so simple anymore.
In the U.S., we got the lead out of gasoline completely by 1995 (except for aviation fuel) due to its neurotoxicity. In place of lead, ethanol or MTBE was added to "oxygenate" gasoline so engines would run without knocking or pinging. Sophisticated fuel injection and ignition computers solved many of the problems with efficiency and combustion in large engines to accommodate these new fuels.
This leaves a problem with small 4-cycle and 2-cycle engines that you find on all this power equipment. Most manufacturers of 4-cycle engines that power mowers, splitters, pressure washers, larger tillers (any that have a crankcase that you fill with oil) now say gasoline with up to 10 percent ethanol is OK. The problem is that there are now fuels at the pump like E85 that contain 85 percent ethanol and E15 with 15 percent ethanol.
The other problem with oxygenated fuels is that the ethanol attacks plastic and neoprene parts found in carburetors, especially older equipment. Additionally, ethanol has great affinity for water so storing it for any period of time will cause problems because it absorbs water from the air.
Here are the current recommendations: if you have older 4-cycle engines, buy non-oxygenated fuel for them. Not all stations have it; however, there are several in Bemidji and others around the county. The fuel will have an octane rating of 91. If you have newer 4-cycle engines, E10 (oxygenated gasoline, 87 octane) is OK but don't let it get more than three months old unless you put in fuel stabilizer.
If you have 2-cycle engines (those that require oil mixed with gas) on any equipment, check the owner's manual for mixture recommendations. Most new engines require a 50:1 fuel to oil mixture; older ones may be up to 16:1. To be safe, use only non-oxygenated fuel in them, 91 octane and then add fuel stabilizer when you mix the gas. This goes for 2-cycle outboard motors also.
Now you can buy fuel in cans that is premixed and contains stabilizer. If you are an occasional user, this may be a better alternative. It will cost about $24 a gallon. For comparison, if you mix your own, the gasoline will be around $4.10, the oil around $1.50 and the stabilizer around $.30 for a total of a little under $6 a gallon. Smaller containers of oil and stabilizer will increase the price.
A good habit to get into is to have separate gas cans for the different fuels your tools require, mark them well and don't let them get old. Using the wrong fuel can eat up a piston in a hurry and cost far more than saving a buck at the pump.
Refer to the revamped and updated University Of Minnesota Extension Service website, www.extension.umn.edu/garden/yard-garden/ for more information on horticultural topics.
In addition, local Master Gardeners will again answer your questions on home horticulture. Call (218) 444-7916, leave your name, number and question and you will receive a return call.