I bought a used Troy Bilt Bronco riding mower (2003 model) for $400 as a small project to understand the small engine. The model and series number are here

Model Number: 13av60kg011
Serial Number: 1b189h10031

Manual can be found here, search for relevant document.

Side by side comparison of Pony and Bronco.

And, understand the Kohler SV540 engine
Engine surging won’t idle smoothly

Here are a list of basic tune up

	
Air filter
	
Fuel filter
	
Engine oil change
	
Spark plug

Here are some useful video on tune up.

This guy gives simple instruction for a basic turn up on a Pony -- suggested every 25 hours.

Tire replacement carlisle available at Walmart

Oil change seems easy.

Potential problem fixing

Working on the carburetor to solve the problem. 

This video hits the engine that I have on my mower.

I will need this repair kit to repair the carburetor.

This fuel solenoid is very important and fragile part located at the bottom of the carburetor. 

How to replace the drive belt, hopefully I never need to do this.

To get the deck off seems quite easy and straightforward.

Here is one good video on changing the timing belt of Honda Pilot.

Here are some note I write on this:

In order to complete the timing belt job, we need to keep track of the following major checkpoints, a.k.a. critical points:

1. Loosen the crankshaft bolt -- deal or no deal situation
2. Timing marks and manually crank the shaft -- extremely critical
3. Pulley tensioner -- when to pull the hydraulic pin 

To facilitate the job, there are steps (some are not shown) to keep in mind

1. Drain the coolant from the radiator -- don't want to make a mess
2. Drain the power steering fluid and then remove the power steering pump -- reverse these later 

Additionally

1. We earnestly need that power tool to loosen the bolts
2. We need a 3/8 or 1/4 torque wrench for water pump -- to ensure all the gasket is properly sealed but not too tight

It seems that I need to fix the car AC system, as a start, let me accumulate some videos.

	
8 possible reasons that clutch fails to engage, pretty thorough.
	
This guy shows the noise diagnosis and fixing on a car AC problem. 
	
Replacing the 2007 Acura RDX AC compressor pulley

If one needs to replace the compressor, there are a few things to keep in mind

	
Make sure the compressor comes with "right amount" of oil, otherwise, we have to supply the oil like shown in this video
	
Make sure to get new O-rings for both high and low valve connection, use the oil to lubricate the O-rings properly
	
Get a manifold meter to monitor the AC system
	
Vacuum the system to -30 on the low side and wait for an hour to make sure it seals well. Then put on the vacuum for another 45 minutes
	
After connect to the refrigerant, make sure to purge the residual air/moister in the yellow feeding line.
	
Turn the AC on and fan on, start to fill the system until the compressor kicks on. Continue adding right amount of the refrigerant