Step 1 would be to test compression. If good, then proceed.

To test compression, remove the plugs, ground the plug leads, and pull over 6 to 8 times each lead. Should be the same, and on that model, around 70 to 95ish psi.

Then test spark. Likely wont have any, but don’t fret. Pop the flywheel, dress the points, clean with acetone and try again!

I would then clean the carb and fuel lines, replace as needed, clean the tank/filter/petcock.

Change the water impeller. Then barrel test her!

Run the fuel/oil mix at at least 24:1, I prefer a little richer on the 5hps, about 16:1.

Let us know how it goes, and post some pics!

Sorry, you will need a compression gauge. If you don’t have one, borrow one maybe from a friend? If not, harbour freight/ princess auto will have cheap enough ones for the back yard mechanic.

Thread the gauge into a plug hole, then pull over 6 to 8 times. Note compression. hit the release button, then do the same for the second cylinder.

For the manual, Im not sure which one you have? Any of the 5hp models will be almost identical for service information.