If it were me, I would either commit to having the engine serviced, or stop flying it.
Eventually, in the back of your mind will always be the thought of the engine quitting.
At that point it just isn't fun anymore, and you're flying with anxiety.

A quick and easy determination of a carb problem would be to simply try another carb. I know it's easier said than done, but other than sending the motor in, you're guessing, and compromising the airplane.

I don't remember, what is the condition of your carb block?

Also, there were some 3W castings that developed cracks if I remember correctly.

I own three 3W's and am not degrading them in any way. Like I said earlier in this post,
at some point most machines need some kind of service or attention.

All three of my engines run great and I like them alot.

With the proper attention, yours will too.

It's got to be one of the big three.
Fuel - Air - or Fire

Good luck_bob