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Briggs surging badly


Charliegates's Avatar
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08-11-14, 05:29 PM   #1  
Briggs surging badly

I recently took apart a carb (bowl carb) on a Briggs Vertical shaft push mower. It is a newer one, using the cup starter. It seems to be about 5 to 6 HP. I do not have models or codes because they are missing (rusted). It is the float bowl type with the auto choke, and spring governed throttle. I took apart the carb to clean it, and before it ran fine. Now, the engine is very hard to start, and will surge to the point of dying. I cleaned it again, and it still is hard to start, and surges badly. I am not sure what to do. Any help will be appreciated very much. I soaked the carb, and blew out all the jets with an air compressor and could see through them.

 
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cheese's Avatar
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08-11-14, 09:21 PM   #2  
Sounds like maybe the o-ring that fits behind the carburetor fell off? Or something is still plugged up in the carb, probably in the bowl nut.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

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08-12-14, 11:42 AM   #3  
No sir, the O-Ring is on the intake still. The bow nut is cleaned, or at least I am positive of the assumption. I was able to see right through the holes on the side. Not sure about the hole on the top of the threads though. How would I go about making sure its cleaned 100%? I blew it out with compressed air yesterday.

 
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08-12-14, 03:41 PM   #4  
I use torch tip cleaners. They cost $4 or so at hardware stores and have several sizes of stiff cleaner wires that you can poke through the hole to clean it. Start with a smaller wire and work your way up to the size that won't push through anymore, and that's when you've hit the edges of the jet and cleaned out the varnish buildup around the hole. That may not be the problem, but it commonly is. Another possibility is the intake where it bolts to the engine. Sometimes they crack or the bolts come loose.


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08-16-14, 01:11 PM   #5  
Thanks Cheese. I took a wire and ran it through all the holes except for the venturi that had bends where I could not see them. That did not fix the problem. I did this:

1) Blew on the end of the gas line, and felt air coming out of the needle seat for the float, also checked with up and down operation, gas dripped out steadily when down.

2) Took wire to the bowl nut, all passages are definitely clean. No blockage, I could see the wire through all holes.

3) Main jet on top of the carb is clean. I can blow, pass a wire, and see right to the top of it.

There are two holes on the bottom part where the nut goes in to (screws)

When I put the carb back on, there was gas leaking through the nut hole on the bottom. I had to tighten it very tight to not leak. I destroyed the gasket that was there earlier. Is it possible that screwing it in too tightly is causing it to not pass gas as through easily? In that case I need to buy a new gasket for it.

I will post a video later of the engine running so you can see what im dealing with. Also, a video of the main jet.

 
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08-16-14, 11:10 PM   #6  
Still a fuel issue. I don't know why it was leaking... bad gasket or leaking float? In either case, it's not a good idea to tighten it down really tight.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

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08-17-14, 12:33 PM   #7  
It was leaking from the bottom of the bowl where the nut is. I think the gasket is the problem. There are two holes on the side of the nut, I think those are the main pickup for the main jet, as it goes up to the top hole, then to the main jet, both of which are clean. I think the gasket gives it a bit more clearance than the nut has without it, allowing the holes on the side to be exposed to gas.

The float is fine, it took it off and shook it around and it had no fuel inside of it. I also dipped it in water and it shot to the surface.

 
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