+1 I have used a Battery Tender (the model w/temperature sensor) for quite a few years now on my motorcycle, jetski and boat- always with good results. But my V-6 outboard doesn't have a rope start provision (unfortunately) so I run dual batteries- and they have to be up to snuff of course.
I cant find the information for a V-6 outboard option or dual battery option on any of the Prius models? I dont think there ever was a rope start provision for the Prius. I dont know but I am pretty sure.
Take off the cover. My friend didn't think so, either. There was no mention of it in the manual. There was only a small notch on the flywheel. It worked.
My 2001 Johnson 150hp has the (dreaded) optical ignition system that's integrated into the flywheel cover- it can't be removed and be able to run the engine with it off- unfortunately the timer base/pickup is in the flywheel cover unlike the legacy models that used to place those components under the flywheel. On that particular outboard model- the flywheel is almost completely shrouded with no provision or notches for rope-start options. It's a major design flaw if you ask me- so I have to be extra careful not to drain my batteries while out on the water. If the kids want the radio on while fishing- I turn the battery selector switch to bat 1 or bat 2 so in the worst case I still have one fully charged battery to start up with. Ole Evinrude wouldn't like what they did with his invention if he saw the plastic carbs and ignition on my outboard...