Bruce, I de-carb my 2000..........200 hp Evinrude FICHT every 50 hours like clock work, makes one hell of a big difference in the way she runs.
Remove the air cover to the 6 air intakes at the front of the engine, [ they look like carburators ].
Sea Foam only comes in a non-pressurized can,.......so you must pore it into a hand sprayer [ for strong chemicals only,...kinda expensive, like $8.00 just for the sprayer, it will melt the cheap sprayer guts ].
Sea Foam also comes in a presurized can but it's called "Deep Creep" [ same solution ] but it's only 12 oz instead of 16.
Start the engine & let it idle [ either on the hose or in the water ].
Spray solution into each air intake, [ you will hear the engine bog down more in some intakes than others ].
Do this as fast as you can because you want to get as much Sea Foam inside the engine as possible before she burns it all up.
When you get to the end of the solution & if the engine is still running, shut her off, it's best if she floods out.
I let it set over night because the solution turns the hardened carbon into a liquid & this allows it to be burned & pushed out the exhaust.
I also remove the plugs after she's cooled down & pore another can [ or enough ] into each cylinder, & turning the flywheel by hand [ no compression witout plugs ] .
This ensures the solution gets in back of the rings & saturates every nook & cranny.
Before starting the engine, turn her over "BY HAND" not with the starter to try & get as much solution out of the cylinders.
When you feel you have removed most of the solution from inside the engine by turning it over by hand, put the plugs in & start her up, but be careful because the engine "WILL" want to over rev, so when you hear her start to rev, shut her off.
You may have to do this 2 or 3 times before she settles down to a normal idle.
There is absolutly no need to rev the engine higher than 1,000 rpms in neutral & no need to run her any harder in the water than 4000 rpms because the carbon is now liquid & it will burn off.
Please note that the engine "WILL" smoke like you have never ever dreamed it could,....it's gonna scare you but don't worry because thats the nature of the beast as it burns off the carbon & excess cleaner.
You plugs are going to catch hell because there's gonna be alotta crap coming out of that engine.
If the plugs are fairly new, I remove [ after the Sea Foam treatment & run for at least 1/2 hour ], clean them with carburator cleaner, brush with small wire brush, re-gap at .028 & put em back.
Trust me, you will not believe the crap thats going to come out of that engine & the smoke "WILL" bring the fire dept so do it some place where it wont draw to much attention.
Your engine will run like it is brand new, idle so smooth & quite & just a big improvement.
Do this every 50 hours & your engine will last you much longer than if you just say, hey, mine runs fine, I'll leave it be.
Do "NOT" run any other oil through that engine other than the XD50 Evinrude oil.
Do not run anything other than the XD50 special oil for DFI engines.
Do "NOT" run the regular TCW-3 oil you ran with a carbed 2 stroke because the DFI & FICHT engines lube from inside the crank case, not mixing the oil with the fuel as the carbed engines did,.....if you do run the regular TCW-3 oil, expect your engine to fail long before it's time & than you can blame the engine like most people do saying it's junk, not because you used walmart X brand TCW-3 oil for carbed engines.
The DFI or FICHT engines are a totally different animals from yesteryear 2 strokes, treat em as so & your engine will be running long after most other brands.
I do this method because I feel if you just put the Sea Foam or "Engine Tuner" in the filter & run it through with the fuel, it gets burned off as soon as it's atomized & sprayed into the chamber & exploded, not allowing it to get in back of the rings where most carbon failures occure.
I learned this method from one of the top guns [ techs] at Bombardier.
Sal