K181 Carb issues

[adsm08 4,327]

The boy went to mow tonight and couldn't get the engine to start. I took a look, and fuel was running out of the carb. So I took it apart, checked the float and needle, they are working at best I can tell. They pass every test I know, I can flip the carb over and not be able to blow through it, I can hold the float up and get no fuel, I can let go of the float and it drops, along with the needle.

 

But as soon as I put the bowl on and prime the fuel system fuel starts running out of the carb.

 

This is one that has had an electric pump installed. Aside from the pump overwhelming the float I'm at a loss.

[ebinmaine 78,094]

6 minutes ago, adsm08 said:

pump overwhelming the float

 

 

What's the exact fuel pump you're using? 

[WHX?? 55,908]

Float not full of gas ... hole in it? 

[pfrederi 20,178]

[Mike'sHorseBarn 3,466]

If the bowl vent is plugged it will do that too.

[wallfish 19,592]

[ri702bill 11,685]

9 hours ago, WHX?? said:

Float not full of gas ... hole in it? 

Yup, a "float" in name only. I've seen a few. If that is the case, best to just replace it.

Are you using the little bent wire clip that loosely attaches the float to the needle? Improperly installed, it can cause the needle not to close all the way....

[WHX?? 55,908]

2 hours ago, ri702bill said:

Yup, a "float" in name only. I've seen a few. If that is the case, best to just replace it.

Shortly after I built the flame it started spewing gas. Yep pin hole in float. I was too stupid to pull the float off and check it just dropped the bowl and checked the valve. I had the bowl off ten times before I got off the recliner and checked the float. 

A very small hole and just for $hit$ & grins tried to repair it. You know just to see if I could. 

Enlarged the hole with a dental pick and shook the gas out and set in a warm place to further evaporate it out. Then just soldered it shut. Being brass soldered up easy. 

 Still working to this day. 

I had pics if I could find them ... 

Edited yesterday at 12:10 PM by WHX??

[sqrlgtr 2,463]

2 hours ago, ri702bill said:

Yup, a "float" in name only. I've seen a few. If that is the case, best to just replace it.

Are you using the little bent wire clip that loosely attaches the float to the needle? Improperly installed, it can cause the needle not to close all the way....

 I hate to admit it, but the little bent wire has bit me a couple times in the past. I've never heard of a e pump going bad and start making more pressure but guess it could be possible.

[peter lena 9,822]

@adsm08   have electrics on my  units ,  2-3.5 PSI  , no issues at all ,  sounds like a VERY TYPICAL COLLECTIVE  ISSUE ,  not one but EVERY stage of  FUNCTION , would recommend an entire carb swap , remove it from the problem , start fresh , like a fuel check valve and filter just before carb ? clear fuel line  , verifies  standing clean fuel to carb !  have that basic  on all my small engines , stand by gen too , no issues , pete    

[adsm08 4,327]

This is the pump I am using, it ran all winter and spring so far on this one. 

 

ENGINEMAN Gasoline Electric Fuel... https://www.amazon.com/dp/B0FBGN2PNS?ref=ppx_pop_mob_ap_share

 

 

The float is empty, not full of fuel by the time I get the bowl off, and I've never had a punctured one drain that fast.

 

I am not sure where the bowl vent is on this carb. I mostly work with fuel injection. 

 

The wire clip actually seems to be MIA. I was in a hurry and didn't realize it last night, but I don't remember seeing it at all.

 

This one has a removable seat. I am not 100% sure the seal between the seat and body isn't leaking, but I can't figure out how to remove it. It is clearly 10mm/ 3/8, but I don't have a socket thin enough and can't get a wrench to swing on it either.

Edited 15 hours ago by adsm08

[sqrlgtr 2,463]

24 minutes ago, adsm08 said:

The float is empty, not full of fuel by the time I get the bowl off, and I've never had a punctured one drain that fast.

all the sunken floats Ive had you couldn't hardly get the fuel out of them so its probably not sinking.

26 minutes ago, adsm08 said:

The wire clip actually seems to be MIA.

I have seen them with and without and don't believe they are necessary. I have had the float needles go bad and that sounds like what you may have. Is the needle all metal or does it have a rubber type tip?

[ebinmaine 78,094]

6 minutes ago, sqrlgtr said:

rubber type

 

Age of needle and seat?

 

Ethanol fuel? 

[WHX?? 55,908]

2 hours ago, adsm08 said:

is clearly 10mm/ 3/8, but I don't have a socket thin enough and can't get a wrench to swing on it either.

Always a problem. Tom @Shynon was turning sockets down and selling them. Originals are 3/8 aftermarkets 10 mm. 

[adsm08 4,327]

2 hours ago, sqrlgtr said:

all the sunken floats Ive had you couldn't hardly get the fuel out of them so its probably not sinking.

. Is the needle all metal or does it have a rubber type tip?

 

I have dealt with that issue on fuel level sender floats as well. I am confident it is not sinking.

 

Rubber tipped needle. Tip feels pretty pliable. 

 

 

2 hours ago, ebinmaine said:

 

Age of needle and seat?

 

Ethanol fuel? 

 

I bought this unit at the show last year. I only use non-ethanol fuel. All history before last June is unknown.

 

If anyone here sold a Commando 8 with a bunch of added lights and a car horn to a youngster for $450 down across from the pavilions at the end of the fair grounds, feel free to chime in on the history.

[ebinmaine 78,094]

My experience shows me that if a carb  EVER had ethanol or MAY have had ethanol (you don't know) then it just automatically gets a rebuild. 

That's become no more negotiable than an oil change.  

 

 

6 hours ago, WHX?? said:

Always a problem. Tom @Shynon was turning sockets down and selling them. Originals are 3/8 aftermarkets 10 mm. 

 

 

A lot of the nut driver sockets that attach to a screwdriver 🪛 handle type driver will work. Not the one piece tool. The little separated bits.  

 

 

[Retired Wrencher 6,553]

I think those K181 run best with a 1 to 2 Psi pumps. Thais what I have on 856 I have. Also I have this on a 1057. Start up turn key and it is all ready running. I hope this helps. You and your son enjoy the ride when done.

[squonk 45,993]

10 hours ago, WHX?? said:

Always a problem. Tom @Shynon was turning sockets down and selling them. Originals are 3/8 aftermarkets 10 mm. 

I have a few I made with my " Poor Mans Lathe!" 

 

[wallfish 19,592]

On 4/16/2026 at 8:09 AM, WHX?? said:

A very small hole and just for $hit$ & grins tried to repair it.

I've repaired a few brass floats. Dry it off, shake it and the gas will seep a wet spot around the hole to identify it's location, if one is there. Make the hole a little bigger to shake out what liquid you can and use napkin/paper towel to help suck it out. Then light it on fire ( Don't worry it won't blow up) and the little flame will also heat the brass creating pressure inside of it pushing out all of the fumes to burn off. Basically burn the gas out until the flame goes out. Solder the hole. The flame burns like the size of a Bic lighter. Obviously not a technique for plastic floats.

It can be done if there's still liquid gas in it too but it takes longer and if you leave it burn too long it can get hot enough to melt the original solder on it. Guess how that was discovered? LOL Do it in steps until it doesn't burn anymore. If you can't hold it with your fingers it's getting too hot. Typically takes about 5-10 minutes from discovery of fuel in it to being repaired and back in the carb good to go. No need to buy and wait for a new one to arrive. Or keep one on the shelf and repair the hole when time allows so it's waiting for the next time. Rinse and repeat. 

 

The vent hole. But it's going to be different on a Walbro carb

 

[squonk 45,993]

40 minutes ago, wallfish said:

 The flame burns like the size of a Bic lighter. Obviously not a technique for plastic floats.