1995 Evinrude 88HP - Muffs vs Water Running Issues

[LG Osprey]

The 1995 Evinrude 88HP that is on my 95 Osprey 17.5 is having a strange problem.

Engine starts up beautifully on muffs, no issues running at idle on muffs up to operating temp. However the minute the boat is launched and in the water at the ramp, thing idles terribly. Have to keep revs high to keep it from dying and the minute you get close to idle speed to put her in gear it dies.

Here are some supporting facts:
-all cylinders pass compression test no problem
-all spark plugs are gapped correctly
-fresh fuel and fuel/water separator
-has not been actively run since 2022 season

Some research online via MarineEngine etc. would lead me to believe its either a spark/misfire issue, a carb float issue, or potentially something with the anti-siphon?

Let me know any and all thoughts on this one... thanks!

[dbiscayne]

Sounds like a carb issue might be time for a good cleaning, they're pretty simple to do. Once its in the water the exhaust sees a lot more backpressure vs. being on the hose, changes the way it idles for sure.
Can you rig up a test tank to run it at home? Really big trash can, don't need to spin the prop.

[LG Osprey]

Yes good idea on large trash can. Will need to do that to replicate issue. Regarding the carb cleaning- you mention it as being simple - is there a way to do that without removal from the engine? I have the shop manual for the motor and the cleaning they recommend seems involved. I’m coming from the world of 60’s inboard motors so this is all new to me.