Carb question on my riding mower

[SpatiallyAware]

It's amazing how much variance there can be from one small engine to the next. Carbs from one manufacturer might be fine while other manufacturers don't tolerate things well at all. Small engines have always had finicky carbs though.

I'm inclined to think that most of the problems in small engines are around EPA emissions regulations rather than e10 though. As emissions have tightened, carbs for small engines have gotten more complex, with multiple jets and more closely controlled fueling, which means that it's much easier to gum up these newer carbs. Older engines basically just dumped "approximately enough" fuel into the intake (tending to err on the side of running rich) because no-one cared about the emissions from a push mower.

The reason that I think this is that e10 has been in use in parts of the US for a lot longer than people have been complaining about these issues. I remember seeing ethanol labels on pumps in Ohio somewhere around 2000 or 2001 but no-one started having "problems" with the fuel until the last few years, which are, coincidentally, the same time that the EPA started phasing in new emissions requirements for small engines. (This is also why things like scooters and small outboards have gone to 4-stroke rather than 2-stroke engines.)

That's my thought on it anyway. I could be completely full of shit. Wouldn't be the first time.

ZV

I agree, and you definitely could be correct.. I really didn't have major ethanol problems until around 2005, I assume that's when it became popular in my area but it could've been emissions stuff too.

My biggest problems were with the motorcycles, I had many bikes at the time and literally couldn't ride them enough to keep the fuel systems from gumming up. It rarely was enough to keep them from starting, but I would have to chug up to a gas station to fill up and they were fine after that.