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

[shrout1]

Ok! So it started and it runs but I have to keep it on full throttle plus about 50% choke. The choke plate looks like it's about 80% closed when it's running successfully (I've been monkeying with everything so this is probably my fault lol). I put fresh ethanol free gas in it and opened the fuel adjustment valve all the way up. If I take the choke off it starts surging and eventually cuts off.

I mentioned that I messed with the governor a little (my mistake) and I'm wondering if I turned it down too low. The dead man switch on the mower seat prevents me from looking down the carb barrel to see if the throttle plate is open all the way when it's running. Forward progress though! And it least it hasn't leaked yet.

 

[Scrubcadet10]

you should be to keep it running by setting the park brake. Blades disengaged.

 

[shrout1]

you should be to keep it running by setting the park brake. Blades disengaged.

Awesome I will give that a try I have only tried to fire it up a few times so far

 

[shrout1]

Ok! Back with more because it's Friday...

As mentioned previously, I've gotten the thing to start but it runs pretty rough and needs the choke closed to keep running. If it only runs at half choke then does that mean my fuel mixture is lean? Not enough gas too much air? I dialed the governor back to factory so that may have something to do with it... Here is some more info...

Here is the position of the choke where I can get the mower to stay running:


Here is the tachometer that I installed... not 100% certain that it's working correctly:

That wire coil does seem to loop back over itself once... I don't want to hit the exhaust manifold or the flywheel

And here is a video of me starting the mower - I was surprised that it actually started. Also, I thought the tach had read 1500 rpm when the starter was going when in reality it was 1200 rpm.

That was a bumpier ride than I was expecting. I'm not sure that I believe the 4-5k RPM reading from the tach. I followed the instructions that came with it and set it for a 4 stroke, 1 cylinder engine. If the RPM reading during ignition makes sense then the tach might be right... dunno.

Another note worth mentioning is that the dead man switch on the seat kills the engine even without the blades engaged. So there is no easy way to stand up; I probably need to jumper something together under the chair.

 

[bertsmobile1]

Yes you are lean
Not enough fuel or air entering after carb
Those induction tachs should only have the pick up wound in one direction , not run back across themselves or tied in a knot

 

[shrout1]

Yes you are lean
Not enough fuel or air entering after carb
Those induction tachs should only have the pick up wound in one direction , not run back across themselves or tied in a knot

I saw a video with a fix for this particular carb that involved removing the limiter from the fuel adjustment knob and turning it up even further than normally allowed. Is there a reason that it would be running outside of spec when it fired up and ran just a couple months ago? It definitely seems lean to me but could the governor be involved? Not being able to look down the carb while it's running does make this a little frustrating. Perhaps I can fix that tomorrow.

 

[hlw49]

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

20-521-01-S is the part no. for the inlet needle and seat along with the instructions to install it. The original seat was brass and would pit over time with the alcohol in the fuel. The new seat is zinc and won't pit due to alcohol. Is $32.00 and change on Amazon.​

 

[shrout1]

20-521-01-S is the part no. for the inlet needle and seat along with the instructions to install it. The original seat was brass and would pit over time with the alcohol in the fuel. The new seat is zinc and won't pit due to alcohol. Is $32.00 and change on Amazon.​

Hey thanks! I have solved that particular issue and now seem to have a fuel mixture problem. I really appreciate you pointing out that part number though! Thank you!

 

[shrout1]

Ok another update. I was able to turn the "low idle fuel adjusting needle and spring" a bit past where the limiter wanted to stop. Not all that hard to do. The mixture definitely got a little more rich. I also adjusted the governor to try and speed up the engine a little because it was keeping the throttle plate nearly all the way closed. It *reaaaaaally* revved up after I did that so I turned it off immediately and tweaked it back down a bit. Seems like I found a happy medium. I need to turn down the low idle speed adjuster a little as I think it's a bit fast when the throttle is all the way down. Here is a video of the latest run. I think the RPM values on that tach should probably be cut in half for it to make sense (I rewired the tach too):

Now, the engine seems to be leaking through a gasket and burning oil - here is that mess: (Edit: This is the valve cover gasket. Taryl Fixes All has a video on replacing it that I might get around to doing... maybe at the end of the season...)

So long as I check the oil levels, does this pose any fire risk? The grass is already starting to grow here in beautiful Alabama and I don't want to risk offlining this mower before I even get started for the season...

Here are some more photos.

I re-wired the tach and zip tied the loop in place. I still think the readings are off...



I bypassed the dead man switch by zip tying a piece of plastic in the contact by the left chair rail. When the driver sits up the spring pulls back on the contact bar, closing the circuit and shutting off the mower ignition. This allowed me to get up and mess around while it's still running. Don't put your fingers in the flywheel

 

[bertsmobile1]

The problem with that gasket is people do it up WAY WAY WAY WAY WAY WAY WAY WAY WAY too tight
This chops up the cork and compresses it so far that it can not do it's job properly
The bolts get done up FINGER tight + 1/4 turn
Before you start use a big flat punch and flatten the region around the hole
Without fail every Courage single I have worked on had deformations around the holes from being done up too tight
Do them up by hand, not is any type of rattle gun / power driver
Start from the bottom then step up left - right and do the same for the bolts inside the V
The idea is you spread the gasket towards the end bolts .
I ride 100 year old bikes
Around 1930 the primary chains got oil tin baths sealed with large cork gaskets
It is no problem to make the joint oil tight .