Outdoor Power Equipment and Small Engines - Deere GT235 w/B&S 18 HP Vertical V-Twin Engine

This Engine recently started loping and/or surging, especially at idle but also somewhat at any throttle setting. I have cleaned and gaped both plugs, replaced the air cleaner and fuel filter, cleaned the carburetor, and changed the oil & filter. However during reassembly I noticed a small (vacuum?) hose about 3/32" inside diameter attached to the carburetor between the choke and the fuel intake that is not (now) connected on the other end. The engine starts easily. If I plug this hose with the engine running it seems to run a little smoother. However, with the hose plugged the engine will not crank. I suspect that this loose hose is the source of the problem, but I cannot determine where the loose end should be connected. Any ideas would be appreciated. The tractor is a little over 8 years old, has been well maintained, and up until now has performed well in spite of rough terrain.

That hose is the bowl vent. It goes nowhere, the hose is just there to keep critters and dirt out of the carb. It should just hang a few inches from the carb. The surging/loping is caused by lean fuel mixture and should be taken care of with a good carb cleaning. Sometimes these carbs are a pain to get clean, and you have to verify that each and every passage is clear and clean.

Thanks Mr. Cheese,
At least I now know I am not crazy or blind.
However I doubt my ability to do much more in the way of carburetor cleaning. Might it be easier to just replace the carb with a new one?

Yup, it would be easier, just not cheaper. It might be the short road to the same destination if you just replace it now though.

Thanks Mr. Cheese.
I have not checked for the exact carburetor needed for this engine, but I have found a new one that is the same series and looks identical for less than $90.
I believe I will check on the exact item needed and order it. I can then replace the entire carburetor which should clear up any other carb problems as well. Then I can work on the old one and if I screw it up, no problem. It I do OK, then I will have a replacement, if ever needed.
If the rules of this forum allow, you might recommend the best source to purchase a new carburetor.
Thanks again.

I don't really know. I don't usually order parts online. Jacks small engines seems to be a popular spot that I've heard good reports about. If you get your carb number, check ebay and you might find a new one there for even less.