Big problems for small engines
Ethanol can be the enemy of any carbureted engine, but the small ones especially suffer
Having problems with your new lawn mower? Is your gas-powered weed-eater hard to start and keep running? Did you put your snowblower away because spring had arrived or because your arm was tired from pulling on the cord? All of these problems and more can be caused by the fuel you put in the tank of your small-engine powered equipment. Basically, if it gets its fuel through a carburetor, avoid ethanol in your gasoline like the plague.
Ethanol or ethyl alcohol is present in just about every fuel we purchase to some extent. Lower concentrations, such as 10-15 per cent, come with low and mid-grade octane gasoline and E85 (for use only in specially equipped and labeled vehicles) contains 85 per cent ethanol by volume. The latter is still rare to find in Canada. It can be wonderful stuff when it comes to reducing our consumption of fossil-based fuels but it can create nightmares for many small engine and marine applications; it’s corrosive and attracts moisture.
In carbureted engines, it will cause deposits in fuel-bowls and will gum up fine jets. It can degrade gaskets and seals, leading to air and fuel leaks. In units that have resin or fiberglass tanks, it will weaken their fibres and eventually cause a fuel leak. Flexible fuel lines can rot out and fail long before their predicted lifespan is complete due to the nature of this additive.
What’s the solution? First, put your carbureted small or marine engine on the wagon (no alcohol). When filling up the garden shed fuel can, look for a fuel station pump with a label indicating no ethanol is present. This almost always means purchasing highoctane gasoline such as Shell’s Vpower brand. Yes, it might cost a few more dollars per season to use this, but it will potentially save hundreds in repair and replacement parts costs.
If you’ve been using regular ethanol-laced fuel for even only a few seasons, take the time to check your small engine equipment. Remove any engine covers and check for leaks or cracks in fuel lines and the tank. If your unit is equipped with a float bowl, remove it to check for deposits (usually small crystalline types, like grains of sand). If you find any, you may want to remove the carb and clean it thoroughly (aerosol spray carb or intake cleaners are available at any auto parts store). If you remove any fuel-mix jets, make sure you keep track of the number of turns it takes to get them out and reinstall them with the same number to avoid losing the correct adjustment.
Rinse and clean the tank and fuel lines as well; sometimes it’s much easier to remove the tank for this job. If a plastic or fiberglass tank is leaking, there are tubes of sealant available for small holes (small engine parts’ stores are your best bet).
If you have everything cleaned and adjusted correctly and you still have a rough idle or erratic running condition, an easy way to check for an air leak due to a failed carb or intake gasket is with the use of a propane torch. In a well-ventilated area, simply direct the propane emissions from an unlit torch towards and around the carb (while it’s running) being careful not to let any into the throttle’s air intake or towards any hot exhaust parts or sources of spark.
If the idle jumps up in the presence of propane, it likely means an air leak into the fuel system where it’s not designed to go. You may be in for a carb gasket/ overhaul kit if the air leak is at the carb.