Hello,

Is it possible to add too much stabilizer? I put in enough to treat 100 gallons but I figure there is only 50 gallons in my tank, which holds 90 gallons. I added some before I pulled the boat out and added the rest before I ran the motor to change the oil. Also, and I apologize if this is a stupid question, but would that make the exhaust smell? I’ve never noticed anything in 20 years but this year there is a burning smell.

Thanks for any help

Probably just wasting product.

And at a high concentration level, I’d expect the smell of the exhaust to change. There shouldn’t be a burning smell though, but what you think is a burning smell may be much different to someone else.

If I was in your shoes, I would make sure to fill it before running and then be easy on her going through the first tank of the season. I do this anyway considering that even with additives the fuel will degrade some.

Products like Stabil say you can't overtreat

I wouldn't worry about it

I think people spend WAY TOO much time worrying about treating fuel over the winter.

ive treated fuel with tanks full, I’ve treated fuel tanks empty, I’ve NOT treated fuel and drained the tanks, I’ve NOT treated tanks and filled them to the brim.

never noticed a difference or had ANY issues and never had anything in the filters.

800HP tall deck NA motors.

just relax and prey winter ends quickly.

PS - my boat sits Sept through May or June at the minimum.

Ive never treated fuel worried about what’s in the tank. Its going to loose octane either way. I’m trying to stop from having to deal with carb or injector rebuilds.

Turning off the pumps and running the fuel out is best - at least for carburetors. Ethanol leaves some real nasty stuff behind. And today’s fuels do not have the additive package that prevents evaporation so the problem is compounded. I literally had a sticky cheese-like substance left in my carburetors one year. Smelled like foot rot, too. Nasty!

Don’t worry.

Mercury’s winterizing instructions for the 300 XS call for a huge concentration of stabilizer and PEA cleaner in the little tank on the engine.

I know a guy on another forum who purposely doubles the Sta-Bil concentration when storing E-0 fuel long-term. Never reported an issue.

Personally, I drain the tank. Take two 5 gal cans to the station and fill with E-0 fuel (used to use AV-gas). Dump in 1/2 quart of 2-stroke oil into each 5 gal can and add a hefty dose of marine Sta-Bil. Pour that 10 gals into the tank. Remove/dump/re-install the fuel filters. Run engs long enough to see the smoke from the 2-stroke oil getting burned, then fog engs until they die. The smell is slightly different but I assume that's more from the 2-stroke oil. Next season, replace the fuel filters, fill-up with 93 oct and that dilutes the 2-stoke oil laced fuel in the tank enough it's no longer noticeable.

Use Techron Marine. It combines fuel stabilizer with PEA cleaner in one bottle.