Kohler Courage 20 / SV600 Walbro 3 carburetor leaking from float valve

[shrout1]

Hey!

I bought a used 2014 Troy-Bilt mower a few months ago and it has been leaking gas from the carb. The carburetor says "Walbro 3" on the side. As I mentioned in the title it is running a Kohler Courage 20 engine and I believe the model is an SV600. The SV470-SV620 service manual matches what I see.

The gas leak is coming out of the jet (insofar as I can tell) and ultimately out of the air inlet by the choke plate which makes me think that 2 things are going on:

1) The fuel shut off solenoid doesn't work (maybe)
2) The float valve isn't seating properly and gas continues to flow into the bowl.

I have a small rebuild kit that has all the gaskets needed for the carb, to include a new float valve needle. The float valve needle currently in the carburetor looks brand new - the guy I bought it from claims to have serviced the carb before selling it. The odd thing is that there doesn't appear to be any kind of a rubber gasket at the bottom of the float valve needle seat... The kit I bought has a small gasket that seems slightly too large for insertion into the seat though the rubber end of the float needle appears to be just the right size for it.

Additionally, if I insert the float valve needle directly into the seat as-is (with no gasket installed) the back of the needle is perfectly flush with the back of the seat; everything seems to play nice together. Still... the darn thing is leaking so I'm kind of at a loss. I'm tempted to spend the $150 to buy a new OEM carb for it but I think I might be close to getting it fixed... any advice would be most appreciated.

Can provide photos if that would be helpful

 

[Scrubcadet10]

Looks can be deceiving with the float needle. There is no Rubber seat in these carbs, as you will see the needle tip is rubber. (Viton)
Post the Model and Spec number of the engine (SV600-_ _ _ _ ) So we can look up the correct parts/check if you have the correct parts.
Also be sure the hole where the needle seats/fuel inlet is, is clean.

 

[shrout1]

Looks can be deceiving with the float needle. There is no Rubber seat in these carbs, as you will see the needle tip is rubber. (Viton)
Post the Model and Spec number of the engine (SV600-_ _ _ _ ) So we can look up the correct parts/check if you have the correct parts.
Also be sure the hole where the needle seats/fuel inlet is, is clean.

Ok! You are 100% correct and thank you for the info so far

The engine appears to be spec number SV600-0224. The needle valve seat *appears* to be clean... hard to get a good picture. I have a replacement needle that I can try but the one that was in there didn't look too bad...

Here are some pictures of the spec, the sides of the carb (dismantled) and the engine sans shroud:

Engine info:

Carb (dismantled):



Side view of the engine (shroud and carb removed):

 

[shrout1]

Ok some more pictures. Here is the bottom of the carb:


Here is a tighter version of just the float valve needle seat:



Here is the float valve needle - the current one:


Is carb cleaner enough to clean this up? The needle doesn't seem like it wants to get stuck when I take it in or out of the seat.

 

[bertsmobile1]

With the float assembled but bowl not turn the carb upside down
The weight of the float should be enough to prevent 7-10 psi of air
With the carb upside down & vertical the float should sit horizontal
If it touched the carb then the needle is too small , too damaged, the float is damaged or the seat is too high .

The carb solenoid does not shut off the fuel supply to the carb.
It plugs the end of the main jet feed so fuel can not enter the engine .
The seat needs to be cleaned
you can cut some scotchbrite , poke it down the hole& twist
Steel wool can be used the same way
I use an end mill or a pencil wire brush between my fingers
Then have a good look at the hole in the seat, some times a very careful twist from a drill bit will restore the edge good enough to make a seal.
The needle in your image is stuffed .

 

[shrout1]

With the float assembled but bowl not turn the carb upside down
The weight of the float should be enough to prevent 7-10 psi of air
With the carb upside down & vertical the float should sit horizontal
If it touched the carb then the needle is too small , too damaged, the float is damaged or the seat is too high .

The carb solenoid does not shut off the fuel supply to the carb.
It plugs the end of the main jet feed so fuel can not enter the engine .
The seat needs to be cleaned
you can cut some scotchbrite , poke it down the hole& twist
Steel wool can be used the same way
I use an end mill or a pencil wire brush between my fingers
Then have a good look at the hole in the seat, some times a very careful twist from a drill bit will restore the edge good enough to make a seal.
The needle in your image is stuffed .

Awesome ty for the pointers!

I believe that the float assembly is behaving the way you mentioned; with the carb upside down it rests horizontal to the ground. Also, I think I have some steel wool lying around, I'll have to try to clean up the seat a little tomorrow. I may have to jaunt out to the hardware store to buy some wire brushes if that doesn't do the job.

You mention the needle in the image being "stuffed"; this is the first time I have ever worked on a carburetor and I am not familiar with the term. I'm very interested to know what that means! Thanks again!

 

[Scrubcadet10]

if you look close at the rubber tip, it appears scuffed, any imperfections can cause it to leak. Bert is from Down Under so either stuffed is the term down there or it was a mis-type. He may not have had his coffee yet.

 

[ILENGINE]

Stuffed either the correct terminology or slang for it is junk and needs to be replaced. And from the pictures the needle is toast and the seat needs a serious cleaning and probably the rest of the carb also.

 

[StarTech]

The inlet needle does appears to be ringed along being dirty.

The OP needs to replace the needle and seat on the carburetor. A known problem area with these Walbro carbs. Now the question is it gravity or pump fed? IPL appears to indicate gravity fed but just need to be sure as there are two different kits for these carbs.

Note: Most online IPLs will not list these needle/seat kits but they are available.

 

[bertsmobile1]

stuffed
A polite way to say bend over & spread em , totally beyond use , etc