Briggs and Stratton engine floods

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  #1  
Old 05-19-08, 01:43 PM
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Briggs and Stratton engine floods

I have a B&S 31H777 18.5 HP engine and everytime I try to start it, gas pours out of the muffler as it cranks. It will eventually start but man does that worry me. Anyone know whats up? Once it runs, no problems. If I stop and a restart, no problem. It just does it when it has sat for a day or so.

Thanks,

Craftsman 42"
Electric Start
B&S 31h777 engine
 
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  #2  
Old 05-19-08, 06:57 PM
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You need to clean/replace the float needle valve in the carb, It's not seating and shutting fuel flow off when sitting. Also check your oil for fuel contamination and change that as well along with the fuel filter and check the fuel tank for trash.


Good Luck
 
  #3  
Old 07-28-08, 01:28 PM
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Red face I have the same engine and problem

I even checked the float and it seems to be ok. Do we need just clean the seat and needle or do you recommend to replace them. Is there anything else?
 
  #4  
Old 07-29-08, 12:08 AM
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Replace the needle. Clean the seat with a q-tip soaked with carb cleaner.
 
  #5  
Old 07-30-08, 10:00 AM
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How do you remove the seat?

How do you remove the seat and replace it.

Originally Posted by cheese View Post
Replace the needle. Clean the seat with a q-tip soaked with carb cleaner.
 
  #6  
Old 08-01-08, 01:04 AM
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You don't...................
 
  #7  
Old 08-09-08, 07:50 AM
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It still floods after a new needlE!

It still leaks gas into the cylinder after I cleaned the seat and added a needle??? When I take the spark plug out after a day gas spills out! Can you help??

Originally Posted by cheese View Post
You don't...................
 
  #8  
Old 08-09-08, 08:12 AM
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How is the float? To properly test a carb is to remove it and disassemble the bowl and remove the float. Shake the float near your ear and listen for the sound of splashing in the float. If it is oday and you replace the needle, reassemble with the float in place tip so the float is on top and check the fuel inlet with a vacuum source to see if it will hold a vaccum. If not the needle valve is leaking or you have a porius casting. You will have to determine why you are leaking. The needle should have a soft tip unless your carb has a soft seat that is pressed into the carb body.
 
  #9  
Old 08-09-08, 08:33 AM
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??

Sorry..Not sure what you mean.."Porius Casting". Do you think I should replace the brass seat? I checked the float and it seems to be ok but maybe I should replace it anyway and how do I do a pressure check??

Thanks..

Originally Posted by CAMINO KID View Post
How is the float? To properly test a carb is to remove it and disassemble the bowl and remove the float. Shake the float near your ear and listen for the sound of splashing in the float. If it is oday and you replace the needle, reassemble with the float in place tip so the float is on top and check the fuel inlet with a vacuum source to see if it will hold a vaccum. If not the needle valve is leaking or you have a porius casting. You will have to determine why you are leaking. The needle should have a soft tip unless your carb has a soft seat that is pressed into the carb body.
 
  #10  
Old 08-11-08, 05:41 PM
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First thing - you can creat a vacuum on the fuel inlet if you do not mind the taste of gas by sucking on the inlet with the carb upside down. I use a hand vacuum pump with a guage so I can see if there is a leak. Second thing - what type of tip was on the orginal needle valve. With a brass seat you could have a soft tip or a solid tip. If you had the solid tip it probably has worn the brass seat and you should replace the brass seat. Like cheese said you will need to cut a thread with a self threading screw into the brass seat so you pull the seat out with the screw. You press the new seat back into the carb casting. The vacuum test of the needle and seat to see that when the float is resting on the needle valve when it is upside down is the best check for leakage there is and the hardest thing to get the new guys to do when learning to repair carburators.

A pouris casting has a crack or hole in it that causes a leak.
 
  #11  
Old 08-11-08, 06:30 PM
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Camino Kid, the needle has a rubber tip. I will remove the brass seat and try to replace it with new one. I hope that does the job. In the mean time I put a fuel cutoff between the tank and carb. This will by me time before I replace the brass seat...

Thanks for your help...I will reply back after I get this fixed...
 

Last edited by usgrandprix; 08-11-08 at 06:30 PM. Reason: OOPS
  #12  
Old 08-14-08, 07:32 AM
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Thumbs up B & S with a Walbro Carb should replace Brass Inlet-Seat

UPDATE:

I was told by a Small Engine mech. that you if you have a problem with the engine flooding(Gas in the oil) you should replace the Needle as well as the Brass Inlet-seat if you have a Walbro carb. He did it for only $5.00...I highly recommend doing the same thing....

It's been 24 hours now and it still doesn't leak or have gas in the oil as well as in the cylinder and starts like new...cross your finders.
 
  #13  
Old 08-14-08, 10:24 PM
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Glad you got it. Sometimes the seat needs to be replaced, but I find those situations are very rare. Most times when a seat needs to be changed, it's because someone stuck something in there and scratched it or the buildup of tarnish and crud is just too much. Occasionally, there is some invisible reason that the seat just will not seal. Sometimes the gum gets on the sides of the seat and keeps the needle from working freely. I don't know how many hundreds of carbs I repair in a year, but I usually have to put a brass seat in less than 5% of the carbs I do. Sounds like yours may have been one of the odd ones.
 
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