Good info guys thanks!
Never really thought about changing out the prop to final tweak things a bit. Makes sense. I don't really like the idea of dragging a sock or bucket. One more thing for a fish to get wrapped in and/or to have to get out of the way with a fish on. We have a couple diff size socks on our jet boat that we use in the river when anchored up for sturgeon or salmon. They are pretty much a must use as sometimes the boat will drift all over the place without one. However ya we have had fish get wrapped in them and they can be a pain at times. On my 11"6 boat, as the driver if I especially get a fish on I still have to steer the tiller, reel in the fish, wind in my downrigger if using down riggers, and if fishing by myself net the damn fish too, lol!!! No desire to have to deal with another variable that could cost me a fish.
Anyway, so ya'll got me now leaning towards an 8 or 9.8. The more I think about it the more I'm thinkin, ya, maybe it is the best overall tool for the job.
Damien is of the opinion that trolling speed between an 8 and 9.8 likely to be the same. Anyone else have any experience here? If this is true I'd likely opt for the extra 2ish hp considering the motor weighs the same.
Also, how about trolling speed between a 5hp four stroke and an 8 or 9.8 four stroke? As long as the slowest trolling speed was pretty similar I'd be happy. Sometimes we troll a fly to prospect a lake and find where the fish are I mostly like to go sloooooowwww like 1mph or so. If an 8 or 9.8 buzzed along way faster than say a 5hp I don't think I'd like the new motor much.
Bigblockfox, yeah if you look on Tohatsu's website you can see the 8 and 9.8 are the same motor (209cc) whereas the 9.9 is 333cc and EFI and 13 or so lbs heavier. Yeah kinda weird 1/10th of a hp more but a pretty different motor.