Magnum Carb

[Racinbob 11,081]

Next poor helpless victim to be terrorized by me wrenching on it is a 1996 Kohler M14. Specifically the carburetor. I have reason to believe it's gunked up by the PO's use of booze in the fuel . It's a very low hour engine (121 when I got it) and was used only to push snow. I suspect it sat for long periods at a time. While at full rpm mowing it has a periodic kinda half of miss. Never timed it but maybe about once a minute? The fuel line is new by the PO. I figure it would be a good idea to go through it. Once I got the air cleaner and associated stuff off I see a big Walbro on the side if it. I picked up a Kohler 25 757 02-S kit for it. Referencing the service manual I'm thinking I'm good to go but I wanted to get the pros opinions. Are Walbros on all Magnums? Did I really get the correct kit? 

 

[Pullstart 62,878]

Bob, I’ve gone through a good handful of carbs.  As long as they are tight, I’ve gotten along just fine by disassembling, setting it all in my gallon of Berryman carb dip for a day or so, and thoroughly cleaning all the passages and surfaces before assembly.

[Racinbob 11,081]

That now looks like the plan Kevin. I've got the Walbro apart and the kit is wrong. The needle valve is a no go. The bowl gasket is different but might work. I can redo the old one. To my surprise the bowl was clean and I didn't see any signs of bad fuel. It just hit me as I'm sitting here eating some lunch. Years ago I ended up with a Walbro kit and never used it. The first box I opened and there it was. I may not use it though. The innards look just fine. I'll just do the Berrymans thing. 

[oliver2-44 9,750]

Be sure to clean the tine holes in the long (and possible short) needle.  I use a stiff wire of a wire brush held in a small vice grip.  

Once clean I like to blow through the bottom holes and feel air coming out the upper holes. 

[ebinmaine 67,498]

2 hours ago, Racinbob said:

needle valve

 

 

If that's a metal needle and seat just check it for obvious wear and tear.

 

If it's a rubber needle or seat just make sure it's still nice and soft and pliable.

 

I don't normally reuse them because I have the carb kit right on hand but I would say that the vast majority really don't need to be replaced when I have them apart.

 

 

I've used a couple different brands of Soaker kits and they did okay but I've been using gasoline which I think works better. This last one that I cleaned up over the weekend, I used lacquer thinner as a suggestion from this website. I believe that works even better than the gasoline.

 

 

Right before I put it back together I take one whole can of your favorite brake clean and spray it all over inside outside backwards forwards up down left right reverse try all that again. Then put it back together.

[Racinbob 11,081]

It is a teensy little rubber tip and in good shape. I soaked it a couple hours and blew everything out with carb cleaner. It cleaned up very well on the inside and out. Just about the only similarity between a Walbro and Kohler is that they are both carburetor. It seems odd that the Walbro isn't even mentioned in the service manual. 

Now it's just a matter of putting things back together.  I saw newer fuel line and figured the PO had replaced all of it. Nope. Just what was easy to get to. I'll go get some tomorrow and replace all of it. The fuel tank bung was seeping so I'll replace it too. 9

 

[ebinmaine 67,498]

@Racinbob

 

Doin' it right...... Nice.

[Racinbob 11,081]

I'm a bit concerned that the little miss issue won't be solved. Unless there was hidden crud it didn't look like it needed cleaning. 

[ebinmaine 67,498]

Do you have a known good carb you could swap onto that?

[Racinbob 11,081]

I have a couple of K-341 Kohler carbs.

[ebinmaine 67,498]

9 minutes ago, Racinbob said:

I have a couple of K-341 Kohler carbs.

 

Yeah. That'll work just fine as a test mule.

 

Even if the linkage won't hook up quite right, you can use a short piece of coat hanger to hold it in place or screw the idle screw all the way in which on a lot of carburetors would bring you up high enough for usage anyway.

[Racinbob 11,081]

I'll probably just put this one back on and cross my fingers. I'm not even sure it's a fuel related issue. I was actually hoping I'd find crud in it. 

[tunahead72 2,412]

3 hours ago, Racinbob said:

... It seems odd that the Walbro isn't even mentioned in the service manual.  ...

 

Check this out, everything you'd ever want to know about Kohler AND Walbro carbs.

Engine Kohler Carburetor reference #TP-2377-E.pdf - Kohler - RedSquare Wheel Horse Forum

 

[c-series don 8,707]

I have found that an easy way to change the fuel line is to connect the old one to the new one with a double barbed fitting. Then you can pull the new one right through without having to take too much apart. 

[Pullstart 62,878]

6 hours ago, ebinmaine said:

Right before I put it back together I take one whole can of your favorite brake clean and spray it all over inside outside backwards forwards up down left right reverse try all that again. Then put it back together.

Amen.

[Racinbob 11,081]

2 hours ago, c-series don said:

I have found that an easy way to change the fuel line is to connect the old one to the new one with a double barbed fitting. Then you can pull the new one right through without having to take too much apart. 

That was my first game plan. Nope. It was tie wrapped tight to some hydro lines. No way to cut the ties. I feel better supporting them too. 

[Racinbob 11,081]

Ok guys. I feel like a total idiot. I've rebuilt many carbs with success but I believe this is my first Walbro. My engine won't start. It's cranking great but won't fire. I've been messing with it for two days now. I've changed things even though I was 99.9% certain wasn't the issue. I've got good fuel flow and spark. The bowl fills properly. I set the two needle valves exactly where there were before. Both were just a fuzz richer than what is called for in the initial setting. But the fuel doesn't get in the cylinder. The spark plug remains dry. When I cleaned the carb it seemed spotless. I soaked it then blew it out with carb cleaner. Yes, in all directions. I just had to walk away totally frustrated. This shouldn't be hard. 

I'll listen to all you guys and give it another shot. In the meantime I'll pull a good Kohler carb in preparation........................

Edited June 28 by Racinbob

[tunahead72 2,412]

Bob, just a couple of questions because I've been there, done that...

 

How much fuel is in your tank?  And the fuel shutoff is open?

 

Did you clean out the needle valve holes like @oliver2-44 suggested?

 

[Racinbob 11,081]

Knowing the pain an underseat tank can be I topped it off before trying to start it. I cleaned the holes extremely well. The valve is open and, as I said, the bowl fills properly. I even tried a cheapy electric pump. In any case I have a good electric on order for it but that won't solve this problem. My next move will be to pull the carb again to check things out. I must have missed something. Not today though. 

Edited June 28 by Racinbob

[Racinbob 11,081]

Another morning shot. Now this has become a lesson in frustration. I disassembled the Walbro again. Even though I was confident it was clean I cleaned it again. Three more cans worth. Every orifice forward and backwards many times. Far more than I've ever felt the need to on the many carbs I've done in the past. I can assure you it can't get any cleaner. Still the same thing. Absolutely no fuel getting into the cylinder. It's fine getting to the carb but it goes no further. 

 

As soon as my wife gets home I'm going to do as Eric mentioned  and drag the 76 to the garage. I'll remove the carb on the K-341. It doesn't need anything. Hopefully that will get the M-14 going.  

[clueless 2,991]

On 6/26/2024 at 1:30 PM, Racinbob said:

I'm a bit concerned that the little miss issue won't be solved. Unless there was hidden crud it didn't look like it needed cleaning. 

Bob, my 312 with the magnum has that little random miss, had it when I bought it with 410 hours. Still does with 645 hour and two complete carb cleanings.

[Racinbob 11,081]

I'm kinda wishing I would have just ignored it now. It wasn't bad but when my wife noticed it..........

I gotta look at the bright side. Right now it's not missing. 

[squonk 41,118]

Give it a shot of carb cleaner whilst cranking. If it doesn't pop, it aint fuel

[Racinbob 11,081]

16 minutes ago, squonk said:

Give it a shot of carb cleaner whilst cranking. If it doesn't pop, it aint fuel

I've been hesitant to do that especially since I have good spark but I'll try it before I pull the carb again.

 

[Racinbob 11,081]

20 hours ago, squonk said:

Give it a shot of carb cleaner whilst cranking. If it doesn't pop, it aint fuel

 

Popped real good. 

 

What's under the welsh plugs? The drawing I have doesn't show. I didn't pull them because the kit I have has one of the right size and one that's too small.