Carb Check Valve - B&S 494775 Carb

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  #1  
Old 12-30-11, 09:33 PM
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Carb Check Valve - B&S 494775 Carb

I give up - where is part 494409 (check valve) on a 494775 carburetor? I have taken this carb apart several times, and don't remember seeing that. Of course, I don't remember a lot of things!!!

Thanks,
 
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Old 12-31-11, 05:22 AM
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Behind the primer bulb at about the 10-o'clock position, if I'm not mistaken. You'll need to remove what looks like an inlet needle seat and behind it you will have a ball (tiny) and spring. And, FYI, it is a primer check valve.
 
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Old 12-31-11, 09:18 AM
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Sorry, I do not see anything at all like that. Are we looking on the outside of the carb? The only thing I see is on the insude - inside the tube which has the screen over it. What is that? It looks like it could be removed by prying it out with a small screwdriver. Is it safe to do that?

The problem I am having is that the mower starts easily, but then dies after a few seconds. The primer bulb works, but then the gasoline flow seems to stop.

This carbuerator is about the simplest I have ever seen.
 
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Old 12-31-11, 04:17 PM
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Now that I think about it, my outside/inside description may not mean much. I was thinking of "outside" as parts that can be seen when the carb is attached to the fuel tank, and of "inside" as parts that can only be seen when the card is separated from the tank. Hope this helps.
 
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Old 12-31-11, 04:48 PM
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You have to take the primer bulb out to see it. What problem are you having?
 
  #6  
Old 12-31-11, 05:38 PM
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The problem is you are chasing the wrong end of the dog, you need a new diaphram, procedure follows:
You need to install a new diaphram kit, it is Briggs part # 795083 or old # 495770 also Lowe's has a kit #5083 which has the same parts.
Here we go:

Remove air cleaner, there are 2 bolts that hold things together, one on the front of the tank 3/8" and one into the block 1/2", remove these bolts, now "slowly" slide the carb/tank off the intake tube and breather tube, now tilt the tank in to release the throttle linkage and waalaa the carb/tank is removed. Check the intake tube to see if the O ring seal and plastic retainer are still on the intake tube, if so remove them and re-install them into the carb. Remove the 5 screws from the carb/tank remove carb(don't loose the spring) now spray all holes, cracks and crevases in both the carb and tank surface with brake parts cleaner, remove the main screen(looks like a thimble), now with a small screwdriver pry out the main jet(carefully) and clean it, check the O ring on the main jet for damage, if it is damaged it must be replaced, reinstall the jet, it can be difficult some times to get it to snap back in place(I use the rounded end of a screwdriver handle). Remove and clean the fuel pickup stem(not necessary if the fuel tank was clean). Clean any junk/rust from the tank. Install the diaphram on the tank then the gasket(no goo or sealer) now carefully replace the carb(the spring will try to misalign the diaphram), tighten all screws a little at a time so as not to crimp the diaphram until they are all tight. Install the carb/tank in reverse order and you are done. If I missed something one of the real mechanics will correct me. Have a good one. Geo
 
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