Walbro LMK carb problem

[gm280]

Okay, I tried this a few days ago and apparently it didn't take. Or if it did the powers at be can delete this.

I have an older Kohler CV15S engine on my lawn mower with a Walbro LMK carb. It started leaking some years ago now and even after installing a few rebuild kits in hopes to stop the leak, it still does. I know exactly what the problem is but was wondering if others had the same problem being how it is a known problem with that type carb all over the web. Seems the standard rebuilt kits include a new needle but not the actual brass seat. And so Walbro came out with a kit well after the problem because known to fix their leaking carbs with a seat kit for only $35 dollars...a third of the price of a new carb and it is merely a screw and a new brass seat. I see some videos that folks use a Q-tip with some polishing compound and literally polish the seat back to a good finish to stop the leak. Has anybody actually done that or even installed their new brass seat in their carb? I have a work around but it is a PITA to remember to turn OFF and ON the fuel valve each and every time... If I forget to turn OFF the fuel valve I installed as my work around after I am finish cutting the lawn, then I get to drain the crankcase oil and filter and install fresh oil and a new filter next try because the carb allowed gas to get into the crankcase. Anybody? :frusty:

 

[gm280]

Re: Walbro LMK carb problem

Okay not one response. Am I the only person with this problem? out:

 

[Idlespeedonly]

Re: Walbro LMK carb problem

I have never had the problem. I would try the q-tip or a small wood dowel with some compound on it. The goo thing with the dowel you can shape the end however you need it to be.

 

[gm280]

Re: Walbro LMK carb problem

I have never had the problem. I would try the q-tip or a small wood dowel with some compound on it. The goo thing with the dowel you can shape the end however you need it to be.

Well actually I took the carb off again today and played around with it and did use some plastic polishing compound first on a Q-tip. That didn't work out very well so I moved on to a drill bit. NO I didn't use the drilling side. I have a complete drill bit set from wire drills through 1/2" in every size you can imagine. So I took the sizes and check them until I found one that just would slide in the brass seat area. Then I applied some plastic polishing compound on the shank and spun it using a cordless drill on the slow setting. I polished the seat area but haven't yet tried it. Tomorrow I'll see... But I do like your idea of the wooden dowel as well and may do that first before reinstalling it... Thanks for a real good idea. I didn't think of a wooden dowel for some strange reason.

 

[gm280]

Re: Walbro LMK carb problem

Update to this thread just incase anybody wants to know the outcome. :watermelon:

So I once again cleaned the entire carb to like new condition. I spent a lot of time with the seat this time, polishing it and make certain it was both clean and smooth without any scratches or issues. I even used a 10 power monocular to verify the seat was smooth. And reinstalled it back on the Kohler engine. Then using a full tank of gas, I turned on the fuel shutoff valve and watched. For about five minutes I thought I beat the problem...BUT then I started seeing gas dripping out of the carb again... So I give up and will use the shutoff valve again. A new seat is $35 dollars and a new carb is $100 at least. BUT the engine and actual mower is over 16 years old now and I also need a new deck. Maybe it is time to buy a new one... Oh and for those that are still reading, the actually needle is like new also without any marks on it either. Oh the pain the pain... :deadhorse:

 

[CharlieB]

Re: Walbro LMK carb problem

Wow, I haven't run into that, yet. It would drive me nuts.

I've had a jack that the check ball would not seal, replaced the ball, same thing. Used a drill bit only turning in reverse to burnish the seat, still no good. An even older guy told me to use a pin puch and a hammer, stike the ball, driving it against the seat to form the seat to the ball. BINGO!!!

First, hopefully your needle is viton tipped so it will conform to the seat. Find a solid steel needle from any other model that will fit in the hole, give it a little love tap to conform the seat to the needle shape, then reinstall your viton tipped needle. You may have to readjust the float level.