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Carburetor needle seat cleaning

#1

A

Auto Doc's

Hello Folks,

Carburetor cleaning can be a chore, but sometimes it takes more than just good carburetor cleaning and a round in the ultrasonic bath. I try to save what carburetors I can to avoid aftermarket copycat versions.

For those that hate Nikki carburetors, I will simply say don't open them unless you put a complete rebuild kit in them. I work on many mower carburetors, but also ATV and automobile carburetors. I've been rebuilding them for many years. But, once in a while I run into one that will give me headaches.

Last week I was working on a problem carburetor on a 2003 Honda Rancher 350 ATV, and it was giving me fits. It has a press in needle seat. No matter how I adjusted the float level it would eventually spring a leak at the bowl overflow.

Finally, I got online to check out some of The You Tube videos and a guy brought up and interesting procedure for cleaning the needle seat and polish it in these ATVs.

Over time gasoline develops a resin or shellac and that stuff is difficult to remove even with the best carburetor cleaner. The solution he came up with was to use a Q-tip with the carb spray. Insert the Q-tip cotton tip into the seat and gently spin it. It cleaned and polished the seat perfectly.

It worked great and I had no more needle leak problems.

Hope this helps someone.

I don't think this same method would work on any 2-stroke handheld carburetor because the parts are way too small.


#2

Tiger Small Engine

Tiger Small Engine

Auto Doc's said:
Hello Folks,

Carburetor cleaning can be a chore, but sometimes it takes more than just good carburetor cleaning and a round in the ultrasonic bath. I try to save what carburetors I can to avoid aftermarket copycat versions.

For those that hate Nikki carburetors, I will simply say don't open them unless you put a complete rebuild kit in them. I work on many mower carburetors, but also ATV and automobile carburetors. I've been rebuilding them for many years. But, once in a while I run into one that will give me headaches.

Last week I was working on a problem carburetor on a 2003 Honda Rancher 350 ATV, and it was giving me fits. It has a press in needle seat. No matter how I adjusted the float level it would eventually spring a leak at the bowl overflow.

Finally, I got online to check out some of The You Tube videos and a guy brought up and interesting procedure for cleaning the needle seat and polish it in these ATVs.

Over time gasoline develops a resin or shellac and that stuff is difficult to remove even with the best carburetor cleaner. The solution he came up with was to use a Q-tip with the carb spray. Insert the Q-tip cotton tip into the seat and gently spin it. It cleaned and polished the seat perfectly.

It worked great and I had no more needle leak problems.

Hope this helps someone.

I don't think this same method would work on any 2-stroke handheld carburetor because the parts are way too small.
Click to expand...
You can also put a wooden Q-tip with valve lapping compound on it and chuck it up in a drill at low speed. Then switch to carburetor cleaner, then blow out the seat.


#3

H

hlw49

You can use toothpaste not the jell the white paste type and a Q tip.


#4

Scrubcadet10

Scrubcadet10

Yep, I always Q tip the seat really good


#5

A

Auto Doc's

The one design I forgot to mention is the carburetors with the Viton seat insert that has to be pressed in. I have not found a good way to clean them, and they are a pain to work with if a new seat has to be installed.

Most of the ones I have come across have the needle stuck badly from old, dried fuel resin and are seldom worth the effort to save.


#6

R

Rivets

Doc, I assume you are referring to Tecumseh carbs with the replacement seats. Personally I have found these are about the easiest carbs to clean and rebuild. Removing and installing a new seat can’t be easier if you have the correct tool. One thing I have found through experience is to always install the new seat dry. For some reason when I first started teaching carb rebuild, adding a small amount of oil resulted in leakage. Never found out why, just always installed dry with no more problems. Here is the tool.
1763581802744.png


#7

H

hlw49

I take shop air and stick it in the fuel line fitting of the carb and blow it out. Tool works great to install it.


#8

A

Auto Doc's

Rivets said:
Doc, I assume you are referring to Tecumseh carbs with the replacement seats. Personally I have found these are about the easiest carbs to clean and rebuild. Removing and installing a new seat can’t be easier if you have the correct tool. One thing I have found through experience is to always install the new seat dry. For some reason when I first started teaching carb rebuild, adding a small amount of oil resulted in leakage. Never found out why, just always installed dry with no more problems. Here is the tool.
View attachment 72326
Click to expand...
Hi Rivets,

I seldom see Tecumseh in my area, but I have dealt with a few small B&S models with replaceable seats.

Usually when I get those, they are salvage or yard sale finds that have been sitting for years with old gas in them.


#9

R

Rivets

My memory is fading, but I can’t remember ever seeing a viton seat on a Briggs engine. Now replacing a brass seat on Briggs is a different story.


#10

H

hlw49

Made a puller to pull them out on Briggs and Kohler carbs with brass seats Kohlers new seats are Zinc and alcohol fuel won't damage them.


#11

Scrubcadet10

Scrubcadet10

Rivets said:
My memory is fading, but I can’t remember ever seeing a viton seat on a Briggs engine. Now replacing a brass seat on Briggs is a different story.
Click to expand...
Is that the seat in the 398188 kits?


#12

H

hlw49

yes


#13

R

Rivets

My apologies this morning. As soon as I saw that number I realized my memory is fading and Briggs did have a replacement viton seat, which I’ve replaced multiple times.


#14

H

hlw49

No problem I know that feeling. Have a good day.


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