08 Mercury optimax 90hp bad injector?

I lost compression in cylinder 1 I took it all apart had it milled out and got on over sized piston. Put new rings on the other 2 Pistons put everything all back together it fired right up but something still seems off. How to I check for a bad injector?

Pull all the injectors and have them serviced before you burn up the engine again. Direct inj and Fuel inj.

Is this not something I can do myself?

Absolutely not, unless you have an injector tester/cleaner. Fuelinjectorman.com He has a fast turn around. You can test the electrical operation but that is pretty much it.

How did you puke the cylinder to begin with?

To be honest I'm not sure I took it to a shop they told me it lost compression on cylinder one and wanted 3600 to mill the cylinder and rebuild it and then go from there two different shops told me the same thing. So I did all that myself. With a machine shop. Put it back and now I need to find the cause. I know I got bad gas so I'm assuming I cligged an injector somehow. I never had a warning alarm or anything it just lost power and would start but wouldn't idle unless it was put in high idle. So as of now it has good compression but I don't want to run it until I find the cause.

Pull the injectors and have them cleaned and serviced.