16hp B&S Vanguard idle surge

[Cupwalker]

Took my Max II out yesterday in snow deeper than I've ever driven it in and for the most part it took everything the 16hp B&S had to move through it at a decent pace. I was full throttle for the majority of the outing and got stuck in a few ditches as well which I'm sure strained the trans and engine quite a bit. By the time I was done probably 20 minutes total there was signs of trans fluid around the vent plug and the engine was surging at idle. The engine wasn't surging before the ride but definitely was after so my question is this. Does the newly developed engine surge at idle have anything to do with the extended full throttle driving I was doing yesterday? That's all I've done lately is repair the damn thing and now this so I'm just trying to get an idea of what might've happened and how big of a problem do I have on my hands. Any feedback would be much appreciated. Thanks Cup

[mfenmor]

Sounds like the dreaded ethanol fuel corrosion in the carb. Pop the top off the carb and have a look. Check the float level and needle is not stuck, and the float actually floats in fuel, they have been known to sink then the engine floods. Inspect everything in there while your at it, air filter, fuel filter, loose wires or screws/bolts.
I only run non-ethanol fuel in mine. No more need for spare carburetors.

[Cupwalker]

Sounds like the dreaded ethanol fuel corrosion in the carb. Pop the top off the carb and have a look. Check the float level and needle is not stuck, and the float actually floats in fuel, they have been known to sink then the engine floods. Inspect everything in there while your at it, air filter, fuel filter, loose wires or screws/bolts.
I only run non-ethanol fuel in mine. No more need for spare carburetors.

Sorry for the delayed response daily grind has been brutal lately. Before tearing into the carb etc I decided to start it the next day just to see what it would do and it wasn't surging at idle anymore but there was still an odd throttle response. When I'd squeeze the throttle lightly but quickly and let go the engine would stumble. Not everytime but several times for sure. So I ran some seafoam through the carb and poured some in the gas tank just to see if that helped. Well, like I said the daily grind has been brutal and I havent had 10 minutes to mess with it so I don't know if it helped or not. Eitherway, thanks for the advice/suggestions they're much appreciated. Cup

[mfenmor]

Seafoam will do nothing for the ethanol corrosion, but if your lucky maybe it's just old gas varnish.

[Cupwalker]

Seafoam will do nothing for the ethanol corrosion, but if your lucky maybe it's just old gas varnish.

Wasn't trying to remedy a possible ethanol problem with seafoam. Was just trying the least labor intensive thing 1st to see what it would do. Thought maybe the carb had gotten a little dirt or something in it. Highly doubt it's an ethanol problem because I routinely maintain the fuel system. The carb was rebuilt about a yr ago and thoroughly cleaned. Everything else in the fuel system was replaced as well. If I didnt use it often/check for fuel system moisture etc I'd say the ethanol deal would be a possibility but that's not the case. Anything's possible so I could be wrong . Eitherway if it doesn't straighten up I'll have to dig deeper. Thanks Cup

[racerone3]

Take off the air cleaner base.rev the engine and cover the carb with the palm of your hand. engine will likely stall. restart and see if its better. if so put the air cleaner back on and go have fun... just some small grit in a jet that got pulled out