Why does an engine surge? Original Message Jan 2, 2012 6:40 pm
I started up my 11.5hp Tecumseh powered Ariens and it was surging. Never did that before. I'm not sure what causes an engine to surge/hunt but here what I did so far in an attempt to correct it. I changed the spark plug, took off and cleaned the carb bowl and needle and float assembly. Cleaned the jets with carb cleaner and ran a fine wire through every hole...even the tiny one. It still surges. Any ideas on what else I should try...or re-try.
Re: Why does an engine surge? Reply #6 Jan 3, 2012 12:56 am
jrtrebor wrote:
Does partially choking it make any difference?
Thanks everyone for all the suggestions. Yes it does help if I partially choke the engine. Linkage all works freely. Haven't made any adjustments...just cleaning. Also I didn't pull the entire carb...just the bowl, nut, needle and float. I changed the spark plug because the one that was in it was carboned up badly. I'll try draining the fuel. The gasoline was in from September with Stabil added to the fuel at the time of purchase. The tank was run dry but in September I got around to replacing the belt and added gas to make sure everything was good with the new belt. I did have a squirrel gnaw a small hole in the gas cap over last winter but I don't think that the "extra vent" would cause a problem.
Re: Why does an engine surge? Reply #7 Jan 3, 2012 8:59 am
You might want to explore the fuel cap vent a bit more. Make sure that it's actually venting. Fire up the engine and loosen the cap. See what that does. The squirrel may have left small particles of plastic that may be impeding the vent.
Location: wisconsin
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Re: Why does an engine surge? Reply #8 Jan 5, 2012 10:23 am
paul 7! everyone above has good advice,i would particularily pay attention to the orifices in the brass nut that holds the float bowl on.use a small wire to wiggle through the holes to make sure they are clean.if there is a high speed needle jet in the center of the brass nut you should be able to cure your surging by going a tad counterclockwise(richer).when it starts if you have to keep the choke on for a long to keep it running you are lean. check all gaskets from carb to intake, and intake to engine.carb clean with jets adjusted correctly,float height set, no breathing leaks,and good fresh gas, engine should run without surging.i would also dump a good shot of carb cleaner in the fuel.
