Briggs 3hp 2 cycle snowblower floods out

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  #1  
Old 01-16-01, 01:44 PM
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I just finished rebuilding a 2 cycle briggs & stratton engine. This was a complete rebuild, piston & rings replaced, cylinder honed out ect... I have great compression and great blue spark, thanks to a new magnito a correct gap to flywheel. I rebuilt the carb, not much to it, however, after it starts, it runs for about 5 min. then it runs down to a stall. After the stall, you can hear the fuel sizzling as it continues to pour into the cyl. I checked the needle & seat, seems to be o.k. (5/16" below bowl floor was the installation directions)I can't restart unless I pinch off the fuel line to clear out the flooded cyl. After a few pulls, it will start then sputter until I release the fuel line. If I partially pinch off the line while it's running (restricting fuel flow)it runs fantastic. There dosen't seem to be much to this carb, but seems to be a real pain in the @#%$% to get set up correctly. It seems that if it's not 100% it won't run.
p.s. I did check the gas cap for restrictions it's o.k., however that would cause a fuel starvation condition.

Any help would be appretiated.

Thanx, Rob B
 
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  #2  
Old 01-16-01, 05:00 PM
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How many adjusters on the carb? The low speed adjuster may be really rich. The only thing that will let the gas in is the needle and seat, or pressure buildup in the gas tank.
 
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Old 01-16-01, 05:29 PM
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There is only 1 adjustment screw, this is the mixture(air) adjustment. I've tried the adjustment all over the place, no improvement.I've also tried running with & without the cap on the tank, no difference. It seems to come back to some internal carb problem??
 
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Old 01-16-01, 08:13 PM
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Hi:shhnappa

You might try switching the diaphragm and gasket. If the diaphragm and gasket are incorrectly installed, <wrong one installed first> this condition could occur. Granted, this isn't likely but does happen.

Be sure the seat under the needle isn't loose. Double check that float setting <besure it's free to float> while you have the carb apart.

Another common error made during a carb rebuild is the reinstalled location of the fuel bowl. It should have a detente for the float to drop down into. If the bowls OEM position wasn't scribbed <scratch mark to note it's position> prior to removal, it may be incorrectly installed.

A bent needle could also cause the problem. That would lead you to think it has seated when it hasn't. Remove it and double check it.

You mentioned that there wasn't very much to the carb. Your correct. However, those simple carb $#@##% can also cause an enormous amount of GRIEF!
 
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Old 01-17-01, 06:18 AM
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Tom,

Thanks for the info. I'm a little confused about the float suggestion. This is a diaphram type carb, therefore there is no float. The seat for the needle is held in with a "c" ring which is pushed down 5/16" with the neoprean seat below it. I'll pull it out and reset it less than 5/16" because I think it's not resting against the needle, even thought that is the measurement I was given in the overhaul kit. Let me know your thoughts on the float question??

Thanks, Rob B
 
  #6  
Old 01-17-01, 11:40 AM
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Hi:shhnappa

I wasn't sure which carb it had on it either. You mentioned (5/16" below bowl floor was the installation directions) which mislead me to believe there was a fuel bowl involved. However, I replied using suggestions for either type of carb.

Once you have the carb together, prior to installing it back on the engine, test it to be sure that no air passes thru it when the needle is closed. A short piece of fuel hose pushed onto the fuel inlet and a lite breath of air should work.

Good Luck
 
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Old 01-17-01, 01:57 PM
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Thanks Tom, I'll let you know how I make out.

Rob B
 
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Old 01-30-01, 07:16 PM
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Tom,

Thought I'd update you. I took the carb back off, & went through this [email protected]$#ing thing real carefully. I changed the needle seat height and adjusted it a little higher than the spec. I also had to re-calibrate the needle hinge tab height to make it 1/16" away from the bowl edge. I also checked all the flow throughout with a rubber tipped air gun at 5-10 p.s.i. After making ABSOLUTLY sure everything looked good, I hooked it back up and it started & continued to run. The real test was to see if it would restart after I deliberatlly turned it off, IT DID!!!
We just got 7 inches of snow, it ran fantastic.

Thanks for all your help,

Rob
 
  #9  
Old 02-01-01, 02:58 PM
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Hi:Rob

Thanks for the update with the sucessful results. Always glad to know that careful attention to minor details, patients and persistence pays off with positive final results, as it has in your case.

We now include you in the group with other HAPPY CAMPERS!!!...hahaha...:-)

Regards,
Tom
 
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