filled the gas tank with kerosene

[FSH 210 Sport]

Oh you know, the injector cleaning, yada yada yada. Just all the extra stuff on the label besides the ethanol and water benefits.

If you run Top Tier gasoline it has a detergent additive package which helps to keep the injectors clean, but, occasionally running Techron fuel system cleaner every few tanks will clean up injectors and the combustion chamber. Techron is the detergent found in Top Tier gasoline. Since you bought the boat used I’d highly recommend running a tankful of Top Tier gasoline with the proper amount of Techron fuel system cleaner through it.

Here’s the problem with ethanol laced gasoline. Ethanol bonds instantly with water, any water that is absorbed into the ethanol is suspended in the gasoline. There is no way to know how “wet” the gasoline is when it is purchased. As fuel is burned the vent for the fuel tank draws in outside air to replace the space where the fuel was, in the case of a boat this air is right next to the water which has a lot of water vapor in it in addition to whatever the surrounding areas’ relative humidity is. This further loads the ethanol with water. Once the ethanol has reached saturation this is when phase separation begins, again, no way to know how loaded the ethanol is at any given time. Products like Star Tron help to prevent phase separation, there is a specific Star Tron formulation for marine applications. In the meantime you’ve got water sitting there in the fuel which is corrosive and is also non combustible. Ethanol has half the BTU’s of gasoline, so there is less energy by volume than non ethanol fuel. Is it a good idea to run an occasional tank of ethanol laced fuel through the system? I think so as it will remove any water in the fuel system, the bottles of fuel system water remover you find in auto parts stores is ethanol, but when I do this I run the tank down very low and replace it with non ethanol fuel. Allowing fuel to sit for long periods with water suspended in it is not a good idea, that whole corrosion / oxidation thing, I know this as I lost a fuel pressure regulator in one of my FI dirt bikes as it corroded and seized due to ethanol laced fuel. Over time the oxygen in the water causes the fuel to oxidize lowering the octane rating of the fuel. I don’t know what your winter boating plans are but most folks store their boats during the off season, if the boat is stored outside, the temperature swings that occur will cause heating and cooling of the fuel and fuel vapor in the fuel tank, as the vapor heats it expands and pushes out of the fuel tank vent, when the vapor cools it contracts and draws in outside air, so a good strategy for storing during the off season is to add the proper amount of a fuel system stabilizer, I use Amsoil, and then fill the tank with non ethanol fuel, then go run the boat around a bit to thoroughly mix the fuel and get that treated fuel through the system before storing it for the winter. By keeping the tank full the amount of vapor is kept at a minimum and the amount the fuel tank breathes is kept at a minimum. The way I look at it, if non ethanol fuel is available it’s well worth the added expense to eliminate any possible issues associated with ethanol laced fuel.

I think you’ve got the fuel usage strategy reversed, if you’re going to be going through a lot of fuel for water sports activities that’s the time to be using the ethanol laced fuel as you will be going through a lot of fuel, the SVHO engine burns 20 gph at WFO and 10 gph at best cruise. If it was me, I’d still be running the non ethanol fuel if available.

If you’re storing the boat outside you’d want to fog the intake tract and cylinders as well. If you don’t run the engine for 30 mins continuously and get it fully up to temp during any given outing to burn off any water vapor in the oil you would want to change the oil before storing it. Don’t put new spark plugs in it until after you’ve burned off the fogging oil in the spring, speaking of plugs, these engines seem to go through plugs much faster than other power sports machines. A lot of folks put in new plugs at the beginning of each season, if the engine ever begins to run rough, has trouble starting or fails to reach max rpm the go to fix is a new set of plugs.