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Briggs wouldn't start today, but ran last night


Nuzzy

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Well, I'm officially confused (though given my knowledge of carbs, this probably isn't surprising). As recently as last night, I had the 16 horse single Briggs running in my 7116. This motor as of a few weeks ago was easily started with a rope around the flywheel (starter was broken at the time). After swapping it into a new frame, the only thing different is that I hadn't yet dialed in the choke; otherwise all linkage had stayed the same. Last night it died on me a couple times after running at lower throttle; I chalked that up to the possibility that I was running with the choke part way on. Still, it would start back up and run. When I went to shut it off, it did backfire once. Fast forward to this morning and it wouldn't start after repeated cranking. Following is the list of things I checked: -unhooked choke cable and tried to start manually putting carb on full choke, half choke, no choke, and various in between -popped off fuel line to ensure flow; no stoppage or restriction in the line -tried starter fluid and it fired right up; ran as long as I was spraying -took carb off and sprayed thoroughly with carb cleaner; took out the cone needle thing, screwed out the fuel rod looking thing, carb cleaned them both and verified all holes in the rod thing seemed unobstructed -put carb back on and still nothing -cleaned spark plug I read through a current similar thread here where many people suggested needing to hold the throttle closed or low to start; tried that with no luck. So, I have a motor which has been recently easily started and ran last night, backfired when stopped, won't start today on the fuel supply but does with starter fluid in the intake, and no fuel flow issues to the carb. Thoughts? Engine model is 326437-0649-01 sm02
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Do you have one of the fuel shutoffs with the knob located at the carb as per 3416 soveriegns? There is a fine screen filter that clogs up with white stuff, if you do, clean it with some laquer thinner, and try it again, or you may have some water in your gas. Float adjustment? Needle sticking? Will it run with a trickle of gas poured into the carb? What kind of spark are you getting? check the points for oil that might have leaked when moving the engine from one to the other. Good luck
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Obvious gas flow problem. Remove needle, is fuel runs out the jet is stopped up. If no fuel the float needle or inlet passage stopped up. Pull the fitting out of the carb and look inside the threaded cavity above the float needle for debris.
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Check for vacuum leak at the block,if you wrestle it around like I do like lifting while useing the carb for a handle It maybe where the problem is. make sure the bolts are tight.
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  • 3 weeks later...
So, as I said above (and going off the recommendations from the other thread), I had previously tried starting with the throttle held closed and close to closed without luck. Well the other day I got to playing with it some more and low and behold, got it to fire and run by feathering the throttle lever on the carb somewhere halfway between closed and wherever the governor springs hold it. I say feathering because I have to make minor adjustments as I "read" the sounds of the motor until it has run for a few seconds; then I can let go, have the governor hold it wherever it wants, and throttle down and up with the throttle lever all I want. Not sure why this finicky behavior all of a sudden showed up, but at least I have a way of starting the damn thing!
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Hi Eric--I'm not claiming to be an expert but if you take out the cone needle thing (emulsion tube) and look very closely near the threads you should find one or two tiny holes that may be plugged which I think work as the idle circuit. I've rebuilt two of these carbs in the past month but can't remember the number of holes. I use a very small torch tip cleaner and carb cleaner followed by the blow gun. One starts perfectly and the other has to have the throttle held to idle. Go figure. Hope this will be of some help.
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Sorry about the double post but as you know the mind is the second thing to go. After you check the above make sure you check adjustments. Initial should be a turn and a half out from lightly seated on both the idle and high speed jet. After warmup turn the idle mixture in until it starts to die and back out until it runs smoothly. Turn the high speed jet in until the engine starts to die, back out until it runs rough and blows a little black smoke and set somewhere in the middle.
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