I've got an old 25 Evinrude on my Jon boat. Starts easy, idles well, revs up fine, but put a load on it and it bogs down. Choke it when it's bogging and it picks up RPM for a couple of seconds then bogs down again.
I'm thinking it's the crank seals? All basics are good, plugs, coils,fuel, etc.
Does it sound like crank seals to you?
Is it worth fixing?
Are parts still available (early 80's model)?

Thanks!

 

Try this site. I'm in the middle of fixing my 70s Orrion and was directed here. It may be useful.
The Hull Truth - Boating and Fishing Forum

 

Bad fuel pump/low fuel pressure/flow. If the crank seals were bad it wouldn't want to idle.