Is it better to run out of gas periodically vs topping off the tank before each use?

[Gord Baker]

I'm asking this about lawnmower engines here, but I suppose this also applies to snowblower engines too, and any other gas powered machine.

I usually top off my tank before each use, unless its late in the season and I'm explicitly trying to run the machine down on gas. And I keep my gas clean, and i drain the gas and winterize at the end of the season, and I put a little seafoam in all my small engine gas, so everything seems fine.

But I see so many youtube videos where they drain the carb or the tank and theres so much dirt or water in the fuel. It seems like it would be kind of hard to get water in a lawnmower engine. You'd have to be gassing up in the rain, but most people aren't going to be using their lawnmower in the rain in the first place. But with snowblowers, its very common to have to gas up while its still flurrying out. Or to just have snow everywhere so when you take the cap off, a little falls in.

So if you run it out of gas, the engine is going to suck in at least the water, if not some of the micro-dirt too and 'burn' it up in the engine and sent it out the tailpipe, preventing it from building up in the fuel system.

Is this sound reasoning? Or are there other factors that make this moot? I almost never do this, but it would be easy to start. Especially with a lawnmower. It would be a little more of a hassle to do it with a snowblower given how big and heavy they are (and mine has tracks so you can't push it, you can only drive it when its running).

I wonder what other people's thoughts are on this?

The water in the tank comes from condensation in the fuel container and the Ethanol process.
I never totally empty the fuel container, always shut off fuel and run engines dry and drain Float Bowl for Winter. That Ethanol (now 15%) can really seize up a Needle valve. Everyone has a different opinion.
That is mine. I am a 'first pull' guy. A splash of Sea Foam in a nearly empty tank doesn't hurt. Run it, let it sit for a couple days and run again.

 

[Gord Baker]

Ethanol Free gas is not available in Canada thanks to Trudoo and his Lieberals.
The cheap fuel now has 15% (e15) ETHAOL. oK for late model vehicles but not for small gas engines.

 

[Auto Doc's]

It is weird that everyone thinks this post is about winterizing.

Hello 1008com,

That is because of the way you initially worded your opening post.

 

[Picarddj]

I'm asking this about lawnmower engines here, but I suppose this also applies to snowblower engines too, and any other gas powered machine.

I usually top off my tank before each use, unless its late in the season and I'm explicitly trying to run the machine down on gas. And I keep my gas clean, and i drain the gas and winterize at the end of the season, and I put a little seafoam in all my small engine gas, so everything seems fine.

But I see so many youtube videos where they drain the carb or the tank and theres so much dirt or water in the fuel. It seems like it would be kind of hard to get water in a lawnmower engine. You'd have to be gassing up in the rain, but most people aren't going to be using their lawnmower in the rain in the first place. But with snowblowers, its very common to have to gas up while its still flurrying out. Or to just have snow everywhere so when you take the cap off, a little falls in.

So if you run it out of gas, the engine is going to suck in at least the water, if not some of the micro-dirt too and 'burn' it up in the engine and sent it out the tailpipe, preventing it from building up in the fuel system.

Is this sound reasoning? Or are there other factors that make this moot? I almost never do this, but it would be easy to start. Especially with a lawnmower. It would be a little more of a hassle to do it with a snowblower given how big and heavy they are (and mine has tracks so you can't push it, you can only drive it when its running).

I wonder what other people's thoughts are on this?

 

[Picarddj]

I'm asking this about lawnmower engines here, but I suppose this also applies to snowblower engines too, and any other gas powered machine.

I usually top off my tank before each use, unless its late in the season and I'm explicitly trying to run the machine down on gas. And I keep my gas clean, and i drain the gas and winterize at the end of the season, and I put a little seafoam in all my small engine gas, so everything seems fine.

But I see so many youtube videos where they drain the carb or the tank and theres so much dirt or water in the fuel. It seems like it would be kind of hard to get water in a lawnmower engine. You'd have to be gassing up in the rain, but most people aren't going to be using their lawnmower in the rain in the first place. But with snowblowers, its very common to have to gas up while its still flurrying out. Or to just have snow everywhere so when you take the cap off, a little falls in.

So if you run it out of gas, the engine is going to suck in at least the water, if not some of the micro-dirt too and 'burn' it up in the engine and sent it out the tailpipe, preventing it from building up in the fuel system.

Is this sound reasoning? Or are there other factors that make this moot? I almost never do this, but it would be easy to start. Especially with a lawnmower. It would be a little more of a hassle to do it with a snowblower given how big and heavy they are (and mine has tracks so you can't push it, you can only drive it when its running).

I wonder what other people's thoughts are on this?

Let's not forget that the condensation process begins not in your fuel tank or gas can but in the underground tanks at the gas station. When they get a truck delivery, it stirs up all the junk in their tanks; the next few customers get it.