What does the EVAP Canister actually do?

alexhammer

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I've just recently bought a Snapper Pro S150xt. Im wondering what the EVAP Canisters actually do? My dealer didn't really explain them to me. Here are two pictures I took of them (I have to fuel tanks one the mower and each tank has a canister this is just one they are both alike)

image-4145779038.jpg



image-1657715804.jpg
 

Malcolm Rypauf

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The canister (actually a charcoal canister) is an evaporative emissions control device. That is, it catches the fumes from the gas evaporating in the fuel tank and then at controlled times, feeds them into the engines intake so they are burnt up and not allowed to escape into the atmosphere.:smile:
 

ILENGINE

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I don't know how old you are, but you may remember the coffee can under the hood of late 70's and into the 80's vehicles, that is a EVAP canister. The previous poster is correct on how it works and what it does. Just don't overfill the tank and allow raw fuel to get into the canister or you will be replacing it.
 

afoulk

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Wow, so they are putting these on mowers now huh? When did they start doing that?
 

ILENGINE

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Required as of 2011 or 2012. have to have evap canisters, low perm fuel line, non vented fuel caps, florinated fuel tanks if plastic. The extra tall caps you are seeing on the new push mowers have the charcoal canister in the cap.

have seen two evap canisters flooded by raw fuel in the past year. Totally destroys them. supposedly it makes a solid brick out of the charcoal, so it can't vent. I believe some of the new riders don't have an evap canister, but there is a line hooked from the fuel tank to the low vacuum side of the intake, therefore the fuel tank actually operates under a vacuum.

Some are set up to where as you use fuel from the tank, the resulting vacuum pulls the fumes back out of the canister. On others the intake vacuum pulls the fumes out of the canister and are burnt in the engine.
 

Carscw

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Mine has the vac hose in the top of the tank hooks to the intake.

(( cowboy up and get over it ))
 

phcaan

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Required as of 2011 or 2012. have to have evap canisters, low perm fuel line, non vented fuel caps, florinated fuel tanks if plastic. The extra tall caps you are seeing on the new push mowers have the charcoal canister in the cap.

have seen two evap canisters flooded by raw fuel in the past year. Totally destroys them. supposedly it makes a solid brick out of the charcoal, so it can't vent. I believe some of the new riders don't have an evap canister, but there is a line hooked from the fuel tank to the low vacuum side of the intake, therefore the fuel tank actually operates under a vacuum.

Some are set up to where as you use fuel from the tank, the resulting vacuum pulls the fumes back out of the canister. On others the intake vacuum pulls the fumes out of the canister and are burnt in the engine.
Sounds like something that would better serve in the trash can.
 

exotion

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Sounds like something that would better serve in the trash can.

Agreed I would probably bypass it if I had one good thing I dont
 

Brucebotti

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I guess its a sign of the times. I believe I read somewhere that even a small push lawn mower gives off more pollutants than a new car.

One interesting sidenote to show how far we have come. I read an article in AutoWeek when Ford came out with the new Boss 302. They said that a 1969 stock Boss 302 just sitting (not running), gave off more pollutants than 200 new Boss 302's driving at 55mph. It's amazing what can be done with modern technology and electronics. I'm sure this is all coming to the lawn mower world eventually (the canister is the start). This will make it more difficult for us old timers to diagnose and repair problems...:smile:

Bruce
 

Thepogo

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Can the EVAP be bypassed?
 
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