Any Ideas

Doski, I have a 75hp four stroke on my 17 1/2 ft boat. I use it to troll all the time, the only thing that I have to do to get it down to 1.5 or lower mph is to put out a drift sock. I know you are talking 2 stroke, I just thought I could give you some info on the fours.

I used to run twin 115 hp etec saltwater engines.  never had a problem with them just make sure your oil reservoir never gets too low.

doski,had a similar problem,although not on a pontoon boat.ended up with an electric trolling motor after trying a  small gas motor on my boat.we have two deep cycle batteries with an isolation switch between them so we can use one for the trolling motor and one for everything else, but can recharge the trolling motor  anytime or switch back and forth.have only had this setup for 1 year ,but so far it's working great,have fished  lake erie all day with no trouble.the iso switch eliminates the need for multiple batteries saving a lot of space and the gas motor keeps the troller charged up.hope that helps you out.
 

Had the motor for 3 1/2 years now. Changed the oil every spring and only changed plugs last year. Talked to the dealer in Conneaut and he said thats all i need to do. Said they are great motors and dont need very much servicing. Thats my kind of motor. I ran the same plugs for 3 seasons and it still would troll at 1.5. And i know you're a member of KCA. I'm still waiting on that jerky.

I've used my Honda for 3 seasons.  Change the gear lube in the fall, the oil in the spring......and add gas as needed all year!  Have a new set of plugs, but haven't felt the need to change them yet.