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Need assistance - Briggs Carb Rebuild


cez823's Avatar
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12-06-08, 11:46 AM   #1  
Need assistance - Briggs Carb Rebuild

I am trying to rebuild the carb from my mower, the motor is a Briggs 12hp i/c. model # 281707 4120. I bought the overhaul kit (#394698) and started replacing components. I removed all of the screws that i could and removed the bottom cup and float. My problem is that I can not figure out how to remove the portion that the float mounts to so that i can replace the components in there. I do not see screws left that could attach to it but there are a couple pins that look pressed in. I can not find anything on how to do this and I am hoping to find a little help here. I feel like I am missing something obvious. I would post a couple pictures but I don't know how to do it using the url. Any help would be great, I didn't even have luck finding a repair manual.

 
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12-07-08, 06:34 AM   #2  
not sure what you mean by
"My problem is that I can not figure out how to remove the portion that the float mounts to so that i can replace the components in there."

the float is held by a pin that is loose and slides out easily.
the needle would come out with the float and the seat is in the hole the needle came out of. some seats are replaceable and some are not. on a removable seat be sure to use a scrwdriver that is 'fat' enough to grip the slot but no so wide as to damage the threads. i usually grind the sides down on a large driver so it fits the seat well and will not touch the threads.

 
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12-07-08, 08:25 AM   #3  
Something in the model number and type number you posted is incorrect. Verify the model number and maybe someone can help.

 
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12-08-08, 04:06 PM   #4  
Yeah sorry about that the model number was wrong it is 281707 0412 01 90061211.
I'm not sure how to explain this exactly but I will try to add some details. I didn't have any trouble removing the float itself, but I can not remove the cast plate that has the mounts for the float. It is the part that has the shaft with the threads. I thought that it might be threaded but after seeing how it is cast I don't think that it could spin without interference. It looks like it should pop out somehow, I am not sure how and I don't want to break it.

 
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12-09-08, 11:19 PM   #5  
That is part of the carburetor housing. It doesn't come off.


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

God bless!

 
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12-11-08, 08:58 AM   #6  
re:

That was my guess but, the rebuild kit came with a new gasket that is about 3" outside diameter and fit right where this part is.

The problem that sparked this rebuild is that my carb was not holding any gasoline it was all draining into the motor and eventually coming out of the exhaust and was in the oil. Sounded like a bad diapraghm or gasket so i bought the rebuild kit. I've never rebuilt a carb but usually can figure this stuff out. Now i feel like these guysBeer 4U2

 
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12-11-08, 04:57 PM   #7  
You said, “my carb was not holding any gasoline it was all draining into the motor”. This is an indication of a sticking or dragging float needle.

Pick up an inexpensive, as in cheap, can of aerosol carburetor cleaner at a local auto parts store and spray all passages, nooks and crannies.

A sticking float needle will allow gas to flow out of the bowl into the engine as you describe. Float needles will often drag, stick or not seat in the needle cavity due to dirt or corrosion. This dragging, sticking or not seating will allow fuel to flow past the needle.

Remove the float and needle and polish the needle, needle cavity and seat. Deposits on the cavity wall or needle can intermittently cause the needle to drag and not fully seat. Use a cotton Q-tip saturated with metal polish and thoroughly clean and polish the needle, needle cavity and seat.

If you need additional help post back. However, do post back with the outcome.

Good luck,
Airman

 
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12-11-08, 10:33 PM   #8  
That large gasket goes up at the top edge of the bowl, to seal it off to the carb housing.


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

God bless!

 
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12-13-08, 08:17 AM   #9  
I am going to work on this now. I have a new needle and everything in the rebuild kit, I'll just replace everything that I can and post the results. Thanks again for your help everyone.

 
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