Yellow hose on top of Kawasaki 18hp fh531v - where does it go!?

I'm a novice small engine repair guy, but after succesfully cleanining and reinstalling the carburetor on my chainsaw, generator, and wood splitter - I figured my Husqvarna YTH1848XP carb would be nearly as simple...and it was. Cleaned everything and went to put back together, but this yellow tube which connects to the top of the carburetor came detached from somewhere else. I can't for the life of me figure out where the other end of this yellow hose goes. Attached a picture and hoping someone here can help. If it helps, the engine started and ran pretty good without the other end of the yellow hose connected to anything. Didn't notice anything leaking out of it either.


Thanks!

JIM

Can only be one of two, 1 overflow pipe, or 2 vacuum for fuel pump. what I can see in the photo I would say overflow pipe.

EngineMan said:

Overflow pipe

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Thanks EngineMan. Sorry for being ignorant, but I can't find a part called "overflow pipe. Does the other end of that yellow tube actually need to connect to something or is it there to just drain excess gas? Sure seems like the end was connected to something, but can't find any flange or hole that would accept this tube. I've searched over engine diagrams in hopes to find out where it goes, but I can only see where it attaches to the carburetor.

If it is a overflow pipe it would take away any fuel from the engine that is very hot or a spark, its on the bottom so should be fine...!

EngineMan said:

If it is a overflow pipe it would take away any fuel from the engine that is very hot or a spark, its on the bottom so should be fine...!

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Gotcha. OK, thanks for taking the time to respond!

JIM

Just a thought but depending on year could be a vacuum line for the vapor recovery system from the fuel tank or charcoal canister.

ILENGINE said:

Just a thought but depending on year could be a vacuum line for the vapor recovery system from the fuel tank or charcoal canister.

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That is also possible...!

I searched for hours, can't figure out where it goes, so it's currently hooked (literally, a factory hook under the engine) and just there. Ran the mower for 20 minutes with no issues so I'm assuming it's an overflow drain or air hose as suggested. Either way, appreciate folks taking the time to provide suggestions.

JIM

As it goes back into the mower, Ilengine will be correct.
It is the fuel tank pressure relief vent.
Pull it off and also remove the fuel cap.
Blow through the fuel tank and you should hear the air coming out of the yellow line.

California has too many public servants sitting in offices high on drugs musing about how they alone can save the planet.
Some of them in the EPA worked out that on a hot day, fuel laden air escapes from your fuel tank ( happens with cars as well) .
So they have mandated a closed loop from the fuel tank to the engine so that the fuel laden air gets burned and not vented into the atmosphere.

As the fuel gets used from the tank, air has to get in, generally via a one way vent in the fuel cap.
However when the tank gets hot, the air heats and pressurises the fuel tank.
Most just run a vent line, usually via a one way valve.
Next step up is to put a charcoal canister on the end of the vent
Final step up is to run the vent to the inlet manifold.

States run by public servants with a functioning brain capable of reasonable rational thought do not bother with all this tosh so you only find it in the manuals for "California" models.

This is one reason when you look at mowers and replacement engines a lot of them are marked
"Not for sale in California"