5HP Briggs & Stratton Problem

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  #1  
Old 10-20-05, 12:13 PM
crimp
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5HP Briggs & Stratton Problem

Hi all, I hope someone can help with a problem. I have a 5HP Briggs & Stratton engine on my kid's go cart. It is a horizontal shaft engine. When I bought the go cart it had not been ran for a while and the tank obviously had stale gas in it. I took the carb apart, replaced the diaphragm, cleaned out the passage ways, cleaned out the tank, cleaned the points and condenser and put it back together. It ran great for about 3 hours and after shutting it off, it wouldn't start back. I took the head off and the intake valve was stuck. Took it off and cleaned it up, seated it with valve grinding compound and it once again ran great for about 3 hours. It then began to die when the throttle was pushed. It would idle ok, but would die when you took off. Once again I took the carb apart and found the longer of the 2 tubes in the carb had a stopped up screen. I took the carb apart and cleaned it all out again, cleaned the tank again, and it ran great. ONCE more, ran for 3 hours and started running really rough, dieing, and seemed to be running rich. Found the flywheel key was almost sheared into, changed it and it ran OK, but not like it did at first. It still seems to run rich, the plug is very black and sooty, after the tank gets about half empty, it quits, and when it does run, it won't idle, and you can hold the throttle open and it backfires out of the exhaust and spits little sparks out. I've rechecked the points, condenser, valves (to make sure they are not stuck), and the carb. Everything seems to be in order. Could I have a burnt or just leaky valve? Also, could someone give me an overview of how this carb operates, what the adjustment on the side does, etc. I really appreciate anyone's help! (So will my kids!!!!)
Greg Thomas
 
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  #2  
Old 10-20-05, 08:55 PM
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black and sooty? not oily? sounds rich. as for points and all, i would replace em anyway, they are cheap to do so. as for the carb, quits with a half a tank of gas? make sure the pickup tubes are intact. not cracked, etc and the screen at the bottom isn't punctured, letting trash by. has foam slosh stuff in the tank? that may be desintegrating. carb has adjustment screws? they are for controlling gas flow basically, too much it'll run rich, usually 1.5 turns out from all the way in snug as a baseline, then fine tune when warmed up. make sure the needles aren't damaged at the ends
 
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Old 10-22-05, 09:27 PM
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With it dying at half tank, I would tend to think the bowl has a hole in it or one of the pickup tubes is cracked or loose.
 
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Old 10-24-05, 07:14 AM
crimp
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Thanks guys for your replies. Here's an update. This weekend I took the head off and cleaned the combustion chamber out. It was very sooty, from a rich mixture, but nothing else seemed out of the ordinary. I removed both valves, cleaned them, reseated both with valve grinding compound and reassembled. I also replaced the points, condenser and plug with new components, removed the carb, soaked, cleaned and blew it out with compressed air and reassembled everything. Now... the engine runs much better, no miss at high rpms, so far it hasn't died at half a tank of gas, but there is still one small problem, when sitting at idle, when you open the throttle it hesitates and half of the time it dies. I understand that these engines will hesitate because there is no accelerator pump, but I've never seen one that was running good die. Just stumble a little. I'm running it a little on the rich side to try to get the hesitation out, but it still dies unless I open the throttle slowly. Any thoughts?
 
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Old 10-25-05, 12:06 AM
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You still have a carb problem. These carbs can be next to impossible to clean entirely. I reccomend soaking it in an automotive bath-type carb cleaner. You shouldn't even have a hesitation at all.
 
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Old 10-28-05, 12:22 PM
crimp
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Thanks cheese. I did soak it for 24 hours in the bath type cleaner. Gum out I think was the brand with a basket in a gallon bucket. Anyway, I've also discovered that the hesitation gets worse the less gas that's in the tank until it finally seems to run out of gas at 1/2 a tank. I can fill it back up and it will immediately run great. As the gas runs lower it starts to hesitate until eventually it quits as if it ran out of gas and won't start back until I fill the tank back up. I'm thinking one of the tubes must have a hole in it. Is it possible to replace these? The longer of the 2 has a connection between the plastic part and the metal part of the tube which would be at about 1/2 a tank. Seems this one would be the most likely to be leaking.
Thanks,
Greg
 
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Old 10-28-05, 12:41 PM
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yes the tubes are able to be replaced
 
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Old 10-28-05, 02:48 PM
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What are the model, type and code numbers of the engine? I'll provide the part number for the replacement parts you will need.
 
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Old 10-29-05, 12:19 AM
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Yes, you can replace the pickup tubes. That would be a place for a problem, but also...inside the tank, the shorter of the 2 tubes fits into a bowl that is in the tank. This bowl often gets rusted where water rests in the bottom. If a hole develops, the engine can still run with a fairly full tank, until the level gets low enough that fuel doesn't fill the bowl from the tank anymore. Normally, the fuel pump in the carb pulls fuel up into this bowl.
 
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Old 10-31-05, 07:43 AM
crimp
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Puey60... I will get the engine # for you soon.

cheese... that is a very good point! I will check this. It does seem to run out at about that level.

More to come!
 
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