Toro engine surging

ken2

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Mar 30, 2015
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My 2019 Toro SS3225 with the Toro built single cylinder engine. Starting surging when it idles. The warmer the engine is the worse it gets. I can manually put the choke on with my finger and it will smooth right out. Starting doing this when I had about 100 hours on the meter this past July. It now has 159.2 hrs. The owners manual said to replace the air filter and spark plug at 100 hours. I replaced both plus the fuel filter. It made no difference on the surging problem. This week I took the carb a part and soaked it in white vinegar, Blew air threw all the passages and ran fine wire through them as well. Tried it again yesterday. At first I thought it was better. As soon as it warmed up slightly the surging came back. Been using Seaform in the gasoline as well.
 

Scrubcadet10

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surging is Lean running condition meaning Too much AIR or not enough GAS. this can be caused by a dirty carburetor, or a leaking intake gasket.
From what i've read that engine is a Loncin LC1P92F-1
there are 3 gaskets where it could be sucking air, I use WD-40 in a trigger spray and saturate the area around the carb and behind it where it mounts and where the gaskets are, if the engine changes speed or blows white smoke, gasket leak.
 

Rivets

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Yogurt, your at it again, Seafoam will not cause surging, love to know where you got your info??? To the OP, the first thing I would check is the idle jet. It is located under the idle speed screw, which you remove and then pop out the jet. The hole in the bottom likes to plug up, run a small stiff wire through to open it. Do so carefully, then reinstall. Here is a service manual for most of the Loncin engines. https://www.toro.com/getpub/70680. Post back if this doesn’t help.
 

ken2

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I played with it more today. If I spray a tiny amount of starting fluid on the little black plastic idle jet under the idle speed screw. it will smooth out and run correctly.
 
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