# Tecumseh tvs 840 carb



## ccrider966 (Jul 8, 2006)

The carb on my snapper mower has a problem. I removed the float bowl and cleaned it out and opened up the jet holes in the brass bolt that holds it on. I removed the float and needle and blew air into the carb fuel inlet. When I replaced the float and needle, the needle did not contact any seat!!!! Did I blow out the seat with air pressure? What type seat is it, one that is screwed in, pressed in, rubber, brass, or what????
As it is, the float just pushes the needle up and does not contact any seat and cannot seal off gas flow! I looked all over the floor for any type of seat I might have blew out but found nothing. 
Where can I find a diagram of the internals of the carb on a 2cycle tecumseh tvs 840 engine??? I need to see how the needle seals off the gas flow.


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## 30yearTech (Sep 14, 2006)

Yes it's a little rubber type seat, and you probably did blow it out with the air pressure. It's a pretty common part, so you should be able to locate one at most small engine shops.


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## ccrider966 (Jul 8, 2006)

Thanks.....I thought it might be rubber, it must be pretty small to fit in there. I hope I can push a new one in from the bottom without removing the carb! Is that possible? I guess you have to really shove it up in there with a tool. There is no need for a new needle then I assume. 
Sure would like to see one then I might understand! Still would like to see a diagram......surely there is a pdf file covering these engines somewhere!


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## 30yearTech (Sep 14, 2006)

Go to the 4 cycle section and there is a sticky post there with links to service manuals. There are diagrams that show how the carburetors are set up.

There are online parts lists that show exploded views of engines and carburetors as well. You can look up Tecumseh engines and order parts from partstree.com

It will be very hard to install a new seat with the carburetor mounted on the engine unless you have unobstructed access to the bottom of the carburetor. The seat goes in only one way and it's hard to tell if it's in right if you can't see it.

Here is a picture of a seat for a Tecumseh carburetor. The pencil is for a size reference.

http://www.hobbytalk.com/bbs1/attachment.php?attachmentid=62015&stc=1&d=1214945473
DSCF1779.JPG


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## ccrider966 (Jul 8, 2006)

*Seat Direction To Install*

I got a new needle and seat and see that the seat is different on each end! I assume the seat goes in with the solid end in first and the grooved end seals against the needle.....I hope so because I installed it that way! 
Now I found that the plastic elbow fitting on the carb inlet had a crack in it and leaks gas badly. I am now trying to cobble up a replacement fitting using copper tubing epoxied to the carb. I think I can get it to work that way anyway.


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## 30yearTech (Sep 14, 2006)

ccrider966 said:


> I got a new needle and seat and see that the seat is different on each end! I assume the seat goes in with the solid end in first and the grooved end seals against the needle.....I hope so because I installed it that way!


Unfortunately the seat goes in the other way, with the groove side down. The needle seats against the smooth side of the seat.


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## ccrider966 (Jul 8, 2006)

*Seat Upside Down*

Just my luck....I looked at it and figured wrong I guess! It works fine though and I hate to redo it. I guess I could get the seat out somehow but just am tired of working on it. 
How would you get the seat out without damaging it?
Thanks for all the help, this forum is great.


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