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b&s 5hp wont run under load


bdunegan's Avatar
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06-15-09, 01:08 PM   #1  
b&s 5hp wont run under load

have a b&s 5hp on a go cart that wont run under load. the numbers on engine are model 135232, type 0139-01, code 960111yb. has new coil and plug, carb has been rebuilt with new diaphram and needle valve and gaskets. all passages are open, and fuel pick-up tube is open with new screen. will set on blocks and run all day idleing, or full throttle. takes throttle good from idle to wide open. but when you ride it, it goes maybe 30 feet and just dies. it will start back within about three pulls, go another few feet and die. this thing is driving me crazy. it has fat blue spark, is getting gas, but wont stay running. i still think it is fuel, but what am i overlooking? any ideas?

 
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cheese's Avatar
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06-15-09, 09:45 PM   #2  
Look in the tank where the short pipe from the carb goes. It goes into a metal cup that serves as a carb bowl. If this has a hole rusted in it, which is a common thing to see, it won't hold fuel long enough to keep full. When the engine is under no load, it may be able to pull enough fuel from there to run, but the added consumption of fuel under a load might be draining it faster than it can fill. Also, if the fuel pump diaphragm isn't filling it properly, it will do the same.


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06-16-09, 06:30 AM   #3  
5hp b&s wont run under load

thanks for the reply. i thought about that when i had carb off. tank has small bowl made in to it.. but the odd thing is, the carb only has long fuel pick up tube. it does not have short tube, nor does it have place in carb for one. i checked this to make sure the first time i had it apart. also diaphram in carb was replaced with new one.

 
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06-16-09, 10:50 PM   #4  
Do you have the spring and cap under the diaphragm inside the carb body, or is it on the outside part of the diaphragm under the cover? It should go carb, spring, cap, diaphragm, then cover.


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06-17-09, 08:55 AM   #5  
5hp b&s wont run under load

yes, i do have diaphram and spring in right, carb, spring, cap, diaphram, cover. i have checked everything i know to check but nothing changes. i am sure it is fuel related, because even if motor is warm, you have to choke it to get it to start. if this carb came with only one pickup tube, then the diaphram is the only way it pulls gas to carb, correct?

 
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06-17-09, 10:48 PM   #6  
It only has one plastic thin tube, but still has a cast piece that drops down into that bowl, correct?


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06-18-09, 08:05 PM   #7  
b&s 5hp wont run under load

no it does not. it has only one tube. thetube it has is metal for about an inch, then is plastic that sticks down into the tank. this is the piece with the wire screen on bottom. the carb does not even have a hole in it for another tube. this is what is strange. i looked at it three different times to make sure it hadnt just rusted off, but it des not even have a place in carb for it. one other thing that comes to mind if it matters, the throttle cable was run to the hand throttle lever, and i unhooked it and run it underneath to the slide that works the governor. i dont think this would matter since it still throttles up and down using the pedal. so what next? i am going to pull carb one more time just to make sure i didnt miss anything, and hook cable back up a it was and see if it helps.

 
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06-18-09, 10:16 PM   #8  
I don't recall any of that style carbs having only one tube. Maybe I'm wrong, I'll have to do some looking to see.


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06-19-09, 06:38 PM   #9  
The part Cheese is talking about should be covered with a fine screen, about 3/4" long & about 7/16" dia... It doesn't stick down very far & the main jet is inside it.. Just for Goofs, Check your valve clearance,, I've run into 3 or 4 this year that had tight valves & the extra load would heat everything enough that a valve wouldn't seal.. Sounds like everything else should work....Roger

 
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06-24-09, 03:44 PM   #10  
b&s 5hp wont run under load

thought i woul try again to post reply. everytime i do, this site says i am not logged in, so i log in again and when i type and try to submit post, it says i am not logged in again. found short tube on carb, and it is part of carb body. cleaned everything, made sure all is open, checked diaphram and all is good, hooked throttle cable back to hand lever where it was and put other linkage(the one that eliminates hand lever) back on, filled with gas and it started on second pull. started this way for a day or two, and i tried it today, and back to square one. plug is dry not getting gas. can put a little in carb, and will start then die. i know all in carb is clear and is getting a fat blue spark from new coil. bout ready to use this thing as a trotline weight. any more suggestions?

 
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06-24-09, 07:52 PM   #11  
Have you checked the valve clearance??? Just wondering from the last post... May not help you but it fixed 3 or 4 for me already this year & they acted as you describe>>> Just a thought,, ,,Roger

 
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06-26-09, 07:25 PM   #12  
Briggs made two styles of these carbs they were called Pulsa Jet or Flow Jet . I cant remember which but one type had two tubes and the other had one just for a long shot make sure your gas cap hole isn"t plugged.If you goggle Pulsa Jet you will find a complete explanation and a how to rebuild on both models the reason they switched from one tube to two was that as the level of gas in the tank dropped the engines ran leaner and were hard starting with under a half tank of gas. The diaphram is the fuel pump these were about the most simple carbs Briggs ever made but I have one apart right now with the opposite problem mines flooding Im going to swap carbs from another running engine because I"ve cleaned and changed the carb parts changed points checked the valve clearance cleaned the carbon and I"m at a loss for ideas If you find a cure please post it and I will do the same,
Kash

 
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06-28-09, 04:54 PM   #13  
i am at a loss for info too, because now it wont start at all unless i add fuel directly to carb, then it just runs till this is burned out, then dies. i checked valves and according to specs they are ok. mine has new diaphram and spring and all new gaskets. i sprayed carb cleaner around base of carb while running just to make sure no air leaks, and none showed up. i have had this thing off and apart a total of eight times, and recleaned each time just to make sure, but now it wont even pick up fuel to run. am bout ready to just junk it.

 
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