My leaky Walbro carb saga

[stevejones]

Just posting this here in the hopes it'll get a search engine hit & help another poor schmuck.

My 2005 Simplicity mower with the Kohler Command engine had a rough fall. Numerous start-ups were accompanied by billowing white smoke...everywhere.

The Walbro LMK carb was leaking fuel past the needle & seat. After sitting for a few weeks earlier this month, it filled the crankcase with oil.

I tore the carb apart & suprisingly, it looked real good. No visible varnish in the bowl. The solenoid was working. The needle looked good. I ordered the standard rebuild kit (which includes a needle but no seat) & replaced the needle, gave it a good cleaning, and reassembled. Still leaked, and I could watch it leak once the fuel was put to it. Came right up and made the bore of the carb all wet.

Saw a tip on the web about polishing the seat with rubbing compound & a q-tip. Tried it - didn't work.

Found an obscure reference that claimed originally the LMK carb had a non-serviceable seat; but due to problems with it a kit was made available. The PN is 12 521 04-S. It's expensive at $38 to my door, but took a chance. FYI - I don't think you'll find this on the online parts diagrams - at least I didn't notice it.

The kit comes with a standard rebuild kit, but also includes a new seat & a screw to remove the old one. Did the change and it fixed my problem - carb is no longer leaking.

Hope this helps the next guy....

 

[Donald]

I have an Ariens mower with Kohler Courage engine and for that one Kohler replaced the carb at no cost if you complained about the carb leaking. It was an issue with the seat corroding.

 

[Lapham3]

To avoid all that I like to just add a fuel shut off valve, if none comes OE, and then make that a part of the startup-shut-down routine.

 

[bubbatime]

All that aggravation and did you check to see how much a new carb is? I've seen guys clean, clean some more, and clean again, tear down, continue tearing down, hours and hours of carb repairs that would have been rectified in 5 minutes with a brand new carburetor. Not sure about your application, but some carburetors are so cheap nowadays you would be crazy to rebuild your current carb. Always check the cost of a new carb first.

Conversely, a fuel shutoff valve would have worked too and will only set you back $3.

I am of the opinion that a fuel shutoff valve should be installed and used any ways...

 

[The motor guy]

Originally Posted By: bubbatime
All that aggravation and did you check to see how much a new carb is? I've seen guys clean, clean some more, and clean again, tear down, continue tearing down, hours and hours of carb repairs that would have been rectified in 5 minutes with a brand new carburetor. Not sure about your application, but some carburetors are so cheap nowadays you would be crazy to rebuild your current carb. Always check the cost of a new carb first.

Conversely, a fuel shutoff valve would have worked too and will only set you back $3.

I am of the opinion that a fuel shutoff valve should be installed and used any ways...


Carbs can be pretty expensive. Not always though, depends on the engine, but most of the time your talking around 100 dollars.

 

[stevejones]

New carb would've been over $130. I'm fine with the route I went.

 

[Warstud]

Originally Posted By: Lapham3
To avoid all that I like to just add a fuel shut off valve


What happens when you want to use it?

 

[JTK]

Doesn't this rider have the fuel tank mounted lower than the carb? (fuel pump required)

If that's the case, an in-line fuel shut-off valve would be pretty useless.

 

[old1]

If the tank was lower than the carb, there is no way the fuel leaked into the gas while parked.

 

[JTK]

Yep. My bad!

 

[stevejones]

The fuel tank is right behind the engine & it's fairly tall. Yes, it has a cam-operated fuel pump. I could've gone fuel shut-off valve, but I felt good enough in my skills to fix it rather than band-aiding it....