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New briggs, new ailment......

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I put a brand spanking new 16hp briggs in my broadmoor this summer, 28q777, very nice! its been running like a new motor should. However, as of the last few times ive use the mower heres what happens. the motor starts to kind of surge or cycle and or slow down when i kick the electric clutch in, as soon as i shut the clutch off, it revs smoothly again. I checked the deck and all spindles are moving freeley with little bearing wear, i look at the clutch itself when in operation, it looks to be working just fine. One note, it starts running funny when mowing uphill??? any thoughts, anyone? Doug

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Good_Ole_JR
Sounds like the carb needs adjusted while under a load. I had to do that to mine. My 12HP briggs on my 3212 would do that. I had to clear the area from kids and dogs and such, then engage my mower then tune the carb. It doesn't run a smooth as I would like while it idles but has plenty of power under load now. Just my nickels worth!

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PatRarick
Doug, Sounds like a plugged fuel filter, or dirt in the carb bowl. The carburetor on your engine has a fixed main jet. Should be just one nut to remove the carb bowl to check. I have found these carbs to be very fussy about any dirt. Pat

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HubbardRA
It definitely appears that your carb is running lean. This is a known problem with the newer engines, since they are tuned to run lean for emissions. Try what the other guys have suggested. I myself have a Vanguard 14 Hp on one of my tractors, and the only way I could cure it was by opening up the diameter of the orifice in the main jet by .001 inch. Don't attempt this unless you have an extremely small set of drill bits and know how to drill a jet. You can't put the metal back after you remove it. Good Luck. Rod H.

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JeffNemes
It's always a good idea to catch the fuel in a clean container when draining the carb bowl so any contamination can be verified. If water is found (seen as clear or muddy bubbles) the entire system needs to be cleaned and the source cheked to prevent it from happening again.

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Guest
Ok, I tried Jeffs suggestion, the gas i saved out of the bowl is clean, replaced filter, and emptied old gas in tank. ITs been raining all morning so i cant try it out yet................thanks fellas ill keep plugging away. One last question, if i adjusted the electric clutch properly when it was new, would it need adjusting again? Doug

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PatRarick
Doug, Did you remove the carb bowl, or just drain it? I have seen very fine sediment get through the finest filter. On these carbs, it settles just below the main jet. Sometimes, it get deep enough to partially plug the jet. Other times, some of this sediment will be drawn up into the jet. If the engine has been sitting, sometimes just overnight, the sediment will sort of "set up", and will not drain out with the fuel. I make it a habit to remove the bowl and inspect for sediment when I drain the fuel. In addition, I always spray carb cleaner through the main jet when the bowl is removed. Draining the fuel into a clean container to inspect for contamination is a good idea. Sometimes, however, when you drain the fuel, you will not see the contaminants until the fuel has time to "settle out". I once found water when I drained a carb. there was a little less than 1 quart of fuel left in the tank, so I drained this into a quart jar. I saw nothing wrong with the fuel. It was not cloudy, showed no water bubbles, or any other sign that there was water present. After the jar had set undisturbed for about three hours, there was about 1/2" of water in the bottom, as well as a very fine layer of rust. As to the clutch, if you had it properly adjusted when you installed the engine, there should be no need to adjust it again for quite some time. Pat

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Pat, good point, good idea, the gas is still in a cup ill take a look. Doug

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