Hard Starting B&S 19.5


Old 09-04-04, 12:05 PM
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Hard Starting B&S 19.5

I hope someone has some advice.. I have a B&S 19.5 hp engine model 42E707-1631-01 on a Sears Craftsman Riding lawn mower. When I bought this mower it didn't start well cold and almost not at all hot. So I put new gas in the mower and bought a carb rebuild kit for it. Installed a new air cleaner, and fuel filter. Now after rebuilding the carb it is the oppsite. It will start right back up after mowing my lawn but when I pull it out of the shed that is a different story. I need to use my battery charger so I can crank it long enough. Then after 40 min. it may pop just enough to disengage the starter, after attempting for 15 more min. or so it will start and run fine. I removed the air cleaner and tried spraying starter fluid in the carb but it didn't even pop once. I did notice however that I can see some gas sputter up out of the carb, isn't this going the wrong direction? Shouldn't the intake stroke be pulling the gas into the carb? Where do I start? Thank you your help.
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Old 09-04-04, 01:47 PM
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The first thing to try would be to remove the spark plug and put in just a squirt of gasoline. You should be able to get it to start in a couple of seconds and it should run for a second or two. If you can't get it to start that way then you need to look for an ignition or mechanical problem. Look for a fuel, fuel delivery, or carburation problem if your engine will start & run for a second or two. Make sure you are using fresh gasoline and that the spark plug is in good condition. Try the above experiment first and go from there.
Old 09-05-04, 12:07 AM
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Sounds to me like it is flooding during the period of storage time. If the fuel inlet needle is not seating properly, it will cause this.
Old 09-05-04, 10:23 AM
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Cheese - I looked down in the carb with the throtle open and sure enough the bottom of the intake manifold is wet. Since the rebuild kit for the carb I used contained a new inlet needle and the needle seat is pressed into the carb, do I start by bending the tab on the float so it starts to seat earlier? The hing pin for the float was free of any rust and every thing seemed to move freely when I put it back together so I don't think that it is being caused by something binding. Also does anyone know what the valve clearence is supposed to be on this engine?

Last edited by BSTheyAre; 09-05-04 at 12:02 PM. Reason: Adding info
Old 09-07-04, 06:24 PM
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Well, I kept trouble shooting this thing and finally did a spark test. (I figured I had good spark, when it ran it ran well.) And what do you know, No spark on one cylinder and not a whole lot more than that on the other. So, one $60 coil, and two spark plugs later, what do you know. It starts. Hot and cold. Now I just need to keep my eye on it to make sure it is not still flooding. If it is I may just put a fuel valve right before the carb and just shut it off when I am done mowing. Thanks to both of you for your help.

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