Hey guys, Im looking to buy a prop for the motor I just purchased from a friend. It is a 1978 85 hp johnson that runs great. It currently has no prop. By the charts, I should use a 15, 17, or 19 pitch prop.

It will be going on my 17' bass boat that weighs approx 2,000 lbs loaded down with gas, batteries, and 2 fisherman.

Any suggestions on which to try first? Trying them out first hand isnt really an option due to a lack of dealers. I'm willing to buy all 3 and just selling them, but I'd like a suggestion as to which to try first.

Thanks guys!

If you have a merc dealer close you can get a test prop.  Its a nice pretty sky blue.  Pay a down payment and test it out then take the prop back unharmed and you get you $ back.  Thats how I figured out which one I needed.  Sounds alot like my boat.  I believe mine is a 17 pitch.  Just remember as you change pitch your rpm's will change.  Same way if you go 3 blade or 4 blade

I'd say a 19 is about as big a wheel as you could turn on that rig.  If you can find someone to "loan" you a 19 I'd start there and look for a target of 5500 rpms. If your holeshot is too laggy or you can't hit the rpm figure you might as well figure on a 17.  IIRC, I used to run a 21p 3 blade on an older 17 1/2 foot pad hull boat running a 115 Evinrude back in the late 70's.  I was just able to spin up to the recommended RPM's with that prop.  

Tip, as you go up in pitch RPMS drop, going down raises them.