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I replaced the float valve and seat on my Craftsman mower (B&S engine; 126M02-6863-F1-12012059; DOM Jan. 2012). I expected the float to be parallel to the carb bowl edge, but it's not. See pic. Float seat and needle are correct part number per my manual and doubled checked against internet resources (398188). New float valve is same length as prior one. Valve seat seated as much as possible, but falls out when the carb is turned over. Interestingly, there was no float seat found when I took it apart. Anyone have any ideas?

View attachment 66996

Did you remove the old seat? Here’s the procedure I use.

Needle and seat replacement.
Remove the carb, and then remove the float bowl. Check the float bowl jet (which is the bowl screw) and make sure the jets both horizontal and vertical are clean and open. Tip the carb upside down and remove the float pin and float with needle attached. Look in the float needle passage and you should see the red float seat at the bottom of the passage. This is where a #5 crotchet hook would come in handy as you need to remove this seat. If you have no hook, but compressed air, you can blow through the fuel inlet and try to pop the seat out. Put your thumb over the passage to prevent the seat from flying who knows where. No air or hook try bending a stiff paper clip to dig the seat out.

I would either give the carb a good 24 hour soaking or have it ultrasonically cleaned at this time.

With the seat out clean the passage way with carb cleaner. Now you must find a drill bit slightly smaller than the passage way, to be used to press in the new seat. Apply a very, very small amount of a very light lube to the new seat. 3-1 oil or lighter, to help seat it better. Carefully insert the new seat in the passage way with the rings on the seat down toward the carb body. Slowly and carefully force the seat down with the back end of the drill bit. Once it is seated, check to see that it did not flip and the rings are up. Next check to make sure that the float does not have any liquid in it. If it does, replace. If everything looks correct, attach the new needle to the float and install with the float pin centered. It everything is correct, the float should seat level to the carb body, when looking at it upside down. If everything looks good reattach the float bowl, making sure that both the bowl gasket and the nut gasket seal properly. Reinstall on the engine and test unit. Remember to have patience and take your time. Good luck, but I don't think you'll need it.

PS: On the side of some Tecumseh carbs you will find a plastic cover. Under this cover will be an idle jet. Remove it and check to see that the jet is open both horizontally and vertically. You should be able to push the old float needle wire through the vertical opening.

Thanks for the inputs, Rivets. Everything you detailed I have already done, meticulously. As I mentioned in my post, there wasn't a seat upon disassembly. When you peer down into the float needle chamber, all you see is a metal orifice. See attached.

Are you sure there is no seat in there? Should see a silver color in the opening, not a rusty color. Also the needle is askew, not straight up n down like it should be. If that is as far as possibly to push the new seat in, there needs to be something blocking it, like the old seat.

do you have a picture of the old needle?

Scrubcadet10 said:

do you have a picture of the old needle?

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Old on the left, new on the right. Old has rubber tip, new has metal tip.

Those are two different needles, used on two different carbs. That means one of two things are going on. 1. Someone has switched carbs on this engine. 2. Your model for this engine is wrong due to poor eyesight or someone has switched shrouds. Briggs has 3 different needles with viton tips. Need to do some detective work.

acat said:

Thanks for the inputs, Rivets. Everything you detailed I have already done, meticulously. As I mentioned in my post, there wasn't a seat upon disassembly. When you peer down into the float needle chamber, all you see is a metal orifice. See attached.

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The brass piece is the seat. It's built in to the carburetor. You won't necessarily use all the parts in a carb kit, they usually cover a few models.

Is that float on upside down?

Wood, the kit he purchased is not used on carbs with brass seats.

Rivets said:

Those are two different needles, used on two different carbs. That means one of two things are going on. 1. Someone has switched carbs on this engine. 2. Your model for this engine is wrong due to poor eyesight or someone has switched shrouds. Briggs has 3 different needles with viton tips. Need to do some detective work.

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That's what I suspected.
Now I have seen the Aftermarket Chinese carbs use a Viton tipped needle, on replacement carbs. So it's the correct carb but the Chinese just use a different needle
Set up

No seat required on that carb. None when taken apart, replacement one falls out.... it's trying to tell ya....I don't belong !!! Without seat, float is level.... isn't it ?

Your carb looks like it could be aftermarket like from amazon. An original briggs carb for that model would not use a brass seat.

Rivets said:

Are you sure there is no seat in there? Should see a silver color in the opening, not a rusty color. Also the needle is askew, not straight up n down like it should be. If that is as far as possibly to push the new seat in, there needs to be something blocking it, like the old seat.

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It looks like the float is on upside down. The part of the float that the needle fits into is the bottom of the float. The bottom of the float should face the carb. The picture shows it backwards.

Pressed in brass seats do not require a rubber seat--the needle have a viton (rubber ) tip and a conventional seat isn't needed. If you're trying to push a rubber seat in there yuo will never get your float right

smallenginerepairs said:

It looks like the float is on upside down. The part of the float that the needle fits into is the bottom of the float. The bottom of the float should face the carb. The picture shows it backwards.

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I wish posters stop barking when they have no idea how the equipment is assembled. The float itself is correctly installed.

If you had read through the whole thread you have found out we done figure out the problem. It is an aftermarket carburetor someone stuck on the engine that uses a Viton rubber tip and a brass seat where as the original carburetor use a rubber seat and a all metal needle valve. The OP is left wither finding a compatibly needle valve or installing a new carburetor.

As a guy whose worked on small engines for over 60 years, I think it's possible but unlikely that you'll figure out your carb through a forum.

Your best bet is to pitch the old one and buy a new one on ebay or amazon for about $15. I know some guys like this or that brand. Ive bought 3 or 4 dozen and never had one fail.

Worth a try and you'll save lots of time and frustration.

If you are holding the carb upside down, the float is on upside down. The float looks like it is on upside down because the top of the float is usually level with the carb body when the carb is held upside down and gravity holds the needle valve closed. The angle position of the float is wrong if the carb is held upside down. Or if the float is unusual and has the float attach plate on the bottom of the float, not likely, but then the photo may be upside down. Item next: if the valve seat is metal, then the needle valve must have the viton tip. Item last: I don't know how much time you have wasted on this carb. but you could get the illustrated parts breakdown for your machine to see if the this is the right carb. OR, You can buy a new carb on the net for about $25.

acat said:

I replaced the float valve and seat on my Craftsman mower (B&S engine; 126M02-6863-F1-12012059; DOM Jan. 2012). I expected the float to be parallel to the carb bowl edge, but it's not. See pic. Float seat and needle are correct part number per my manual and doubled checked against internet resources (398188). New float valve is same length as prior one. Valve seat seated as much as possible, but falls out when the carb is turned over. Interestingly, there was no float seat found when I took it apart. Anyone have any ideas?

View attachment 66996

Click to expand...

The needle you need is going to have a rubber tip. Before attaching it to the float, make sure it'll go in and out of the needle slot easily.
After installing correct needle, turn the carb as you have it in the first pic. The float should be level. And with your lips, blow into the fuel inlet to see if it leaks air.

OP hasn’t been around for since Oct. 14 and I doubt he’ll be back. 2+2 doesn’t equal 4 in this post and I think someone switched carbs on him and he doesn’t want to admit it. Unless he comes back with more info, trying to help him is a waste of time.

Rivets said:

OP hasn’t been around for since Oct. 14 and I doubt he’ll be back. 2+2 doesn’t equal 4 in this post and I think someone switched carbs on him and he doesn’t want to admit it. Unless he comes back with more info, trying to help him is a waste of time.

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i've run into it on a few quantum engines, where the owner had already bought an amazon special, and it has a viton needle it and brass seat.
his best bet is probably to get a new carb, Briggs or cheapo.

Someone has switched carbs on that or you got the wrong parts from the engine numbers.
The vast majority of vertical crankshaft Briggs & Stratton push mower engines and especially all the Flathead or L heads as they call them have the carb everyone was thinking this is where it has the little orange rubber seat up inside the hole with a metal tipped needle valve.
This is the type of carburetor that goes on some of the higher horsepower overhead valve Briggs engines and most riders that has a brass seat up inside of the carburetor and a rubber tipped or viton probably needle valve.

What happened was you put the orange rubber seat up inside when it didn't need it and that's what gave the extra length and pushed the float down.
You need to take the rubber seat out and if you do it with compress air you can save it for future use. Then you should polish that seat up because it looks quite nasty.
Some people use toothpaste q-tip etc and some just clean it with a q-tip and carb cleaner.
You can also use a metal polish like flitz etc or brasso and on the bad ones that leak if I don't have a replacement I typically use fine valve lapping compound come with both course and fine.
Then I use just a clean q-tip to polish it a little more later. I often use a cordless drill to do this polishing and they come out like shiny brand new brass. Then you have to make sure you use car cleaner and compressed air and blow all the polishing agent out of there and get it absolutely clean before you put your float and the new rubber tip needle back in.

Rivets said:

OP hasn’t been around for since Oct. 14 and I doubt he’ll be back. 2+2 doesn’t equal 4 in this post and I think someone switched carbs on him and he doesn’t want to admit it. Unless he comes back with more info, trying to help him is a waste of time.

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October 14th of this year? That's nothing.
It is funny how people don't come back though. I guess they get what they need and don't care about anything else.
Or sometimes I think we offend some people when we point out their mistakes etc and they're just embarrassed or feel like it's confrontational etc but oh well this is how we learn.
I did submit a reply which you'll probably see but you're absolutely correct as that's not a very common carburetor on the brakes push more engines anyways but certainly the parts he has and tried to use do not go with that carburetor.