Auto Doc's
Lawn Addict
Hello Miles1,
Are you using E-10 fuel or non-Ethanol? E-10 does not burn as efficiently.
Is the blade sharp? A dull blade makes the engine work harder. They don't put cheap blades on these.
How tall and thick is the grass being cut.
Are you operating the mower yourself or a slow-moving kid who thinks they are getting paid more by dragging out the job?
Are you using E-10 fuel or non-Ethanol? E-10 does not burn as efficiently.
Is the blade sharp? A dull blade makes the engine work harder. They don't put cheap blades on these.
How tall and thick is the grass being cut.
Are you operating the mower yourself or a slow-moving kid who thinks they are getting paid more by dragging out the job?
Only use non ethanol gas. Blades are sharp. This time of the year I am mowing about every 3-4 days. My grass is really thick though. Is it possible for the valve adjustments to be off to cause excessive fuel use? I am comparing this to another hrx217 that I have, that doesn’t use as much gas. Like I said before it is not blowing any black smoke. I don’t see any leaks anywhere either.
Auto Doc's
Lawn Addict
Are you getting your non-Ethanol fuel from a dedicated pump with its own service hose? (My local stations have dedicated pumps for only Ethanol.)
Or, from a "pick the fuel" style pump with only one service hose? There is a difference.
Valve adjustment does effect fuel efficiency. Black smoke would be grossly rich, but slightly rich is not so obvious. What is worse is a mixture that is borderline too lean.
A new spark plug with the correct air gap is also helpful.
Another issue that can happen is if the fuel filter is choking down. I think these have a tiny filter pencil style filter in the fuel tank outlet. Strangely enough, it does happen, and the engine will use more fuel due to higher operating temperatures.
I have had this phenomenon happen with portable welder units and generators several times.
Fuel filters can create some strange issues.
Or, from a "pick the fuel" style pump with only one service hose? There is a difference.
Valve adjustment does effect fuel efficiency. Black smoke would be grossly rich, but slightly rich is not so obvious. What is worse is a mixture that is borderline too lean.
A new spark plug with the correct air gap is also helpful.
Another issue that can happen is if the fuel filter is choking down. I think these have a tiny filter pencil style filter in the fuel tank outlet. Strangely enough, it does happen, and the engine will use more fuel due to higher operating temperatures.
I have had this phenomenon happen with portable welder units and generators several times.
Fuel filters can create some strange issues.
Thanks for your reply explaining how a fuel filter being too restrictive can actually cause engine to use more fuel than normal. I do get non ethanol gas from a dedicated pump. Maybe I got some bad gas. I will make sure when I compare mowers, I will be using the same gas for each one. I will switch spark plugs to see if that makes a difference.
Last edited:
GearHead36
Well-Known Member
Do both mowers run the same RPMs? Are both air filters clean? Or, the same amount of dirty? Same blades? High lift blades will use more fuel than mulching blades. Bagging, mulching, or discharging setup the same on both? Check the cooling fins. A rodent could have made a nest in one of them, which would cause that one to run hotter, possibly MUCH hotter.