You might try the Mercury forum.

A Mercury service manual should be available from Mercury Marine or a Mercury Marine dealer.

Here is a link to a chart so that you can decode the serial number to the year of production.

Mercury Outboard Parts by HP / Serial Range

No much luck by following your suggestions.

Wouldn't work if I followed manual of similar Yamaha outboard since it is same internals.

I managed to remove the carburetor. I need some basic instructions

Yamaha service manuals have little to no specific information. Particularly for do it yourselfers. Mercury manuals generally have much more detailed information.

Hi, you may also find these useful on the types of fluids to use if cleaning with an ultrasonic cleaner Ultrasonic Cleaning Carb Housing - Kemet Ultrasonic Cleaning Carburettors - Kemet

Pull the carb.

Remove the float bowl, usually 4 screws that will be hard to remove.

They'll be a float (goes up and down, held in with a pin). Once you remove that
there's a float needle that allows fuel to flow (or stop depending on the fuel level inside).

Pay attention to how the float possibly attached to the needle. Some sit in a slot or have a spring, some don't.

You'll see several orifices and there should be TWO orifices where when you look inside, there's a brass jet. Flat head screwdriver used.

It'll likely be stuck so spray with PB Blaster or other penetrant. Make sure your screw driver fits tight on the jet or you'll destroy it. Grind the edges of a correct screw driver if need be, it MUST fit correctly...

Remove the jets. They usually varnish up and the small holes in the jets clog up. Use carb cleaner on those with an air compressor. **You MUST be able to see thru ALL the orifices**

If there's an external air screw adjustment, gently turn it in and COUNT how many turns till lightly seated-RECORD the #. Now you can remove that one and spray cleaner thru there.

95% of the carb issues are in those TWO JETS being closed off.

For around rubber parts, I prefer brake cleaner as its not as hard on the rubber parts.

Lastly, make sure the float doesn't leak, IE hold it under water and check for
any bubbles/leaks.

Good luck and post back please..

Wonder about condition of water pump after storage?

+1 ^^^^

Someone just recently got one running and the WP came apart causing more issues...