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

Scrubcadet10

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  • / Kohler Courage 20 / SV600 Walbro 3 carburetor leaking from float valve
The problem with that gasket is people do it up WAY WAY WAY WAY WAY WAY WAY WAY WAY too tight
WAY WAY WAY WAY. can't say it enough...
i use stubby nut drivers so i don't over do it. 1647726137208.png
 

StarTech

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  • / Kohler Courage 20 / SV600 Walbro 3 carburetor leaking from float valve
1647726289570.png

I use the following when applying RTV, Install screws finger tight for 12 hrs and then torque to spec.
 

bertsmobile1

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  • / Kohler Courage 20 / SV600 Walbro 3 carburetor leaking from float valve
Interesting
The only gasket we seem to get here is the cork one
I usually go 2-5-4-1-7-3-6
But that is only after flattening the cover
Nearly every one I have come across the holes are dimpled in from being over tightened .
Possibly the original design was to be pressed from thicker steel
 

shrout1

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  • / Kohler Courage 20 / SV600 Walbro 3 carburetor leaking from float valve
Interesting
The only gasket we seem to get here is the cork one
I usually go 2-5-4-1-7-3-6
But that is only after flattening the cover
Nearly every one I have come across the holes are dimpled in from being over tightened .
Possibly the original design was to be pressed from thicker steel
Mine also appears to be overtightened. The rim of the valve cover actually looks bent to me... I have some sealant and a new cork gasket on the way.

Also tried adjusting the low speed idle screw but the thing doesn't seem to want to idle under 3k rpms... Not sure...
 

shrout1

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  • / Kohler Courage 20 / SV600 Walbro 3 carburetor leaking from float valve
And some more pics / video because I want you all to hear and see what this is doing.

I got it fired up and running again, but this time I changed the setting on the tach. Sure enough, at half the measured RPMs from before this thing makes a little more sense:


It seems like it doesn't want to idle correctly. It won't go below about 2.7k rpms, even at low throttle. The thing is still running a little choppy too. It seems like I can smooth it out by turning the low idle fuel adjusting needle to a really rich position; not sure if that is working as intended. That was the fix from another video I saw. It also gets a little smoother as the engine warms up.

So... here is a blown out diagram of the carb from the service manual:

Walbro_LMK_Carburetor_Diagram.jpg
I have tried backing out the low idle speed adjusting screw and spring with the mower running and no matter how far I back the screw out, it doesn't seem to make a difference in the low-throttle idle speed. In contrast, if I tighten idle speed adjusting screw then I can get the engine to run faster at low throttle. This is in accordance with the idle speed adjustment instructions from the service manual:

Idle_Speed_Adjustment.jpg

So is the main jet messed up or what's the deal? This is the first carb I've ever worked on so I don't have a lot of perspective. It seems like this thing can only be adjusted for low throttle idle and I have that turned up so high that the mower is just running on "low idle" all the time. Does that seem at all likely?
 

shrout1

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  • / Kohler Courage 20 / SV600 Walbro 3 carburetor leaking from float valve
Ok still working on this... Got some Berryman chem-dip and the carb just went in for a bath. Current problem: Valve cover.

This dumb mower has an extra bracket installed that is pinning the valve cover in place... Here it is from the front:

Valve_Cover_Front_25pct.jpg

And here it is from the back:

Valve_Cover_Rear_25pct.jpg

I am tempted to think that I have to remove the muffler before I will be able to get the valve cover off. I don't think I own a set of torx (or whatever those particular screws are called) wrenches large enough to remove the connection. Additionally, I will have to get a replacement gasket... Annoying. I may have to use the old push mower this go round... Ugh. I'm not sure I even understand why this additional bracing was put in place... perhaps other mowers support the muffler from below...

This mower is a "2014 Troy-Bilt Bronco" and the frame design is a real pain in the rear. This thing reminds me of working on my old 1999 Maxima... nothing in the engine bay *really* made sense. We'll get this thing fixed eventually...

Also, any pointers on removing RTV cleanly from aluminum? It looks like someone else performed a very similar fix to myself some time ago and I am going to have to redo it...
 

Scrubcadet10

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  • / Kohler Courage 20 / SV600 Walbro 3 carburetor leaking from float valve
Rubbing alcohol works good at removing RTV.
I believe those screws are T50 torx bit
MTD 710-1314A
 

shrout1

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  • / Kohler Courage 20 / SV600 Walbro 3 carburetor leaking from float valve
Rubbing alcohol works good at removing RTV.
I believe those screws are T50 torx bit
MTD 710-1314A
Thanks!

Super close on the torx; they were T-45! I had some large allen wrenches that happened to have a T-45 in them... I hated having to loosen the muffler, but it will mow the lawn with a loud exhaust just as well as with a quiet one. A new gasket has been ordered but I'm hopeful that I'll be cutting the lawn on Monday before I could even install it.

I'm curious - the motor was manufactured in 2010 but the seller told me that the tractor is a 2014. Does that make any sense? I would think the tractor would be a 2010... it's possible that whoever makes Troy Bilt was just using up old engines. Either way, it should run well by the time I'm done so age isn't an issue.

I got the valve cover off and also chem-dipped the carburetor. The main and idle jets all allowed carb cleaner through when I blew them out. Hopefully 4-1/2 hours in the bath was enough. Also took about 2 hours to painstakingly remove the old RTV that someone had used on the valve cover in a previous attempt to fix it. I have a can of "The Right Stuff" and a new cork gasket so I'll be trying that trick tomorrow. Fingers crossed!
 

shrout1

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  • / Kohler Courage 20 / SV600 Walbro 3 carburetor leaking from float valve
So, I reattached the carb, did "the right stuff" trick with the valve cover gasket and reassembled almost everything. I finger tightened the valve cover bolts with the socket and then did about one extra turn with the ratchet. It seemed snug but I didn't kill it. I also put a quart and a half of 10-W30 in it after draining it out to pull the valve cover yesterday. I'll fire it up after work tomorrow, too late tonight to do anything. I had to detach the muffler entirely to get everything to go back together... I *hope* the gasket doesn't leak, but if it does then I have a replacement in the mail already anyway.

I'll get a video of it running tomorrow, assuming it starts up and runs. It's on the battery charger for now, want to make sure it's ready to go. If the blade deck still works then I've got myself a nicely fixed up riding mower. Fingers crossed...
 

shrout1

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  • / Kohler Courage 20 / SV600 Walbro 3 carburetor leaking from float valve
Ok so now it's running too fast :p I tweaked the governor back to the recommended factory setting but that doesn't seem like it matters...


Thing is running like gangbusters. I have a new governor spring hiding somewhere... could that be the problem? I turned the idle fuel jet as low as it can go, but even when I crank the throttle all the way down it doesn't seem to matter. It's a "unitized" cable system and choke works (choke is manipulated by the throttle cable as well) but the thing is just running like crazy from the get go. Now with the main jet unclogged I feel like it's just in overspeed all the time. I'm not sure how accurate my tach is, but you can hear how fast it's going and it seems like the throttle makes no difference at all.
 
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