On sngine bogs down

[Cat Nap3]

I have a Honda df25a outboard motor. It's a 3cyl, 3carb motor. It ideals and runs good once its reved up.
I use gas extender and carb cleaner all the time.
The problem is that the motor Boggs down (will not eccelerate guickley) when shifted into gear. If I fool around with the throttle I can usually get to rev up, although sometimes it stalls. It will start up in neutral immediately. We have ethanol 10 0/0 gas in the US.
All 3 carbs have been changed at some point. The motor is 20 yer old but as I said it runs perfectly. It's on a sailboat.
Any suggestions ???
Thanks. Nick

[a64pilot]

You may can isolate the problem cylinder by pulling spark plug leads one at a time, but that is the classic symptom of a lean cylinder from a dirty carb.

[GordMay]

Greetings and welcome aboard the CF, Cat Nap.