Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

It simply sound like you've got a dirty carb.
The fact that it used to perform better than it is now.
Sounds like you've got a dirty fuel system.
A fuel filter should pick up stuff coming out of the tank.
But it won't filter out everything.
You can build up debris in the fuel bowl itself.
Small bits of varnish, small amounts of water. Tiny, tiny bits of rust scale if you have a steel tank. .
It only takes a any extremely small particle to cause problems in a carb.
If you haven't messed with the carb yet.
I would simply try opening up the needle on the bottom.
An 1/8 to a 1/4 of a turn (clockwise) and see if that makes any difference.
Just spraying, usually won't fix things.  You have to remove the main jet and
run a small wire into all of the small passages.
This link will show you some photos of the small passages.

You're both correct.
I probably should have been clearer about that
I assumed that that carb was still on the engine.
So looking down at the carb. and reaching underneath the bowl.
You'd be turning it CW to increase the flow.

You could try putting the bucket up against something that won't move.
If you have a smooth concrete floor in a garage would be a good place;
The tires should be able to spin on that surface.
Run the throttle up put it in first gear and engage the drive.
That would put a decent load on it.
If he's going to clean the carb out.
Then he'll have to reset the needle from scratch. And adjust it with the engine running.
You do the initial setting by slowly screwing
 the needle all the way in, and stopping when you just start to feel a little resistance.
That is it coming in contact with the seat.
Then you back it out 1 1/2 turns.  That is your initial setting or starting point.
You start it, let it warm up.
Then run it up to full throttle. You start turning the needle in slowly until you hear the engine start to drop in RPM.
Then you turn it slowly the other direction (opening it up) until the engine again starts to sputter or drop RPM.
Then you turn the needle back in to set it between those two points.
So if you turned it in a half of a turn.  Then turned it out a full turn.  You would then turn it back in a 1/2 turn.
That's the static way to set it (no load).  Which will usually work out pretty well.  If the carb is good and clean.
Of course if when you put a load on it, and it doesn't handle it well.
Then you would need to open the needle up a little more. Until it does.