Anyone Love a Mystery? Strange 2-Stroke Outboard Problem

[nuku34]

My latest yacht came with a 5 year-old Parsun 3.6hp 2 stroke. I believe all of these engines are made in China (along with everything else on the planet). After a year of my use, I can say this engine has been absolutely brilliant. It almost always starts on the first pull with no choke, and runs very well.
Other than changing the gear oil, occasionally running it in a barrel of fresh water, taking the stretch out of the throttle cable (once), adjusting the idle mixture screw (once), and using clean, fresh 50:1 petrol mix, I've done no maintenance.
Its a better engine than my pervious Mercury 3.2 which never started on the first pull.
To the OP: I'm following along as your problem might appear on my engine later on.

[richwest3]

Nuku34, I would like to suggest that while you have replacement parts available, you should consider the following...

Fuel tank (mine cracked after a couple years)
Fuel cap (my vent screw stripped out)
Spare carburetor (this was the issue with my engine)

Even with the trouble I've had, I am still very pleased with my Parsun.

[richwest3]

Problem solved!

I replaced the carburetor (with an almost identical Tohatsu carburetor as that was all I could find here in Indonesia) and wow, what a difference.

I believed that there was not mixture adjustment other than jet sizes. There's a screw on the side of the carb that looks like it should adjust mixture, but it only sets the idle speed (unscrew for a slower idle).

I found that there is a mixture adjustment. Removing what Parsun calls the seat and needle, acceleration valve, there is a circlip that controls the position of the needle in relation to the cylindrical air valve. Moving this circlip more towards the blunt end of the needle will lean the mixture.

I put some pictures and more info here: https://twoatsea.com/parsun-carburetor-issue/