Fuel additives--Which one(s)

Jeff Reardon

Jeff Reardon

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What does everybody use in their outboard fuel?

I'm especially interested in what other owners of smaller 2 strokes use.

I have an early 00's 3.5 hp Tohatsu 2 stroke, and an early 90's Yamaha 15 hp 2 stroke.

I had been adding Stabil only when leaving a tank of fuel for a long time. In the past year, I've taken to adding Stabil to all my boat fuel when I fill the tank. Never had a water problem in either engine. My nephew, who is something of a backyard mechanic, suggested I keep up with the Stabil, and add a little Startron, too. I've been doing that this season without a problem. It's a little bit of money, but my motors are small so I'm still on the small containers of both additives I bought back in April or May. If it does no harm, I'm happy to have a little more peace of mind.

But, being a skeptical sort, I wonder.

This stuff might as well be pixie dust or some potion from Hogwarts for all I know about it.



What do the additives actually do?

Is there any reason to use one over the other?

Am I doing any harm by using both?

Is our fixation on ethanol gas just a clever marketing technique for the makers of magic elixirs? (Again, never had a fuel water problem in my motors . . . .)

Fire away. In the meantime I'm still looking for the Philosopher's Stone. I figure if I add a chunk of that to my fuel tank, my motor will run perfectly forever.
 
If you can get a line on some pixie dust you will be all set. I hear the glitter that sometimes comes out when unicorns fart rainbows also works.

Seriously, I don't know. I've had water in my fuel twice (maybe 3 times) and it isn't fun. I have a water seperating filter and treat my fuel and dont' run old gas. I use Seafoam in my outboard and Stabil in everything else. My yamaha F40 does not like Startron, but really likes Seafoam.

I don't understand why my tractor (JD X500) has no problem with old fuel, but my outboard does.
 
A few bucks for Stabil is better than the bill when you have to have your outboard motor serviced from the ethanol gumming everything up... I use it in my duckboat motors (15hp 2 stroke Johnson and 25hp 2 stroke Yamaha) and my fishing boat engine (115hp 4 stroke Yamaha).
 
Ethanol absorbs water. From what I've read, Stabil and other additives change ethanol's chemical make up so it's not as likely to absorb water into your fuel.
 
Hey Jeff, I've been running the Marine Stabil in "ALL" my engines for two or three years now. From my ATV and snowmobile, to my outboards, both the Honda 75 that I just sold, to my 1996 15hp Evinrude, my 1996 Merc 50 4 stroke, to my chainsaws, lawnmower, snowblower, weed wacker and so on. If it uses gas, it gets the stabil. I haven't had any issues with the engines, they all start when they should and run good. The only thing that doesn't is my truck, that tank always seems to be empty!!!
 
I'm with Tod on this one. I use Seafoam in my F90 as well. I know more guys that have had fuel related problems this year in their outboards. I've heard it's because of all the corn their putting in the fuel now, but I don't understand why it's just affecting outboards?

Todd
 
Lee Harker made a point years ago to me that has stuck with me and I have since confirmed with several small engine mechanics. IF the gas evaporates (think longer term storage over winter) you are left with a residue from Stabil, similar to the varnish in it's ability to clog or just plain cause mischief. Sea Foam is more volitle and will evaporate cleaner, in addition does a better job of protecting the gas from absorbing water. That said, I now use that in all my motors, lawn moters to outboards. Since then, most of my motors actually run a bit smoother.

Just some food for thought, as always your mileage may vary.
 
I was talking about this with an outboard mechanic a couple of weeks ago. He said they had been seeing so many problems that they decided to test ethanol content from various gas stations in the region. They found the percentage all over the map--from 8% to 20% ethanol in fuel advertised to be no more than 10%.

To follow up on Eric's post--I had a lawn mower carb gum up while using stabil a couple of years ago. Since then I switched to Seafoam for everything. Seems to work well.

Rick
 
Currently in the US and mainly in the midwest you will find E10, E20 and E85 gasoline. Some gas pumps have the sticker stating Ethanol content no less than 10% but most don't. Ethanol lobbist in 2009 pushed and got the government to okay the use of E20 and now it will probably become the norm in the next few years.
 
I use Stabil blue (for ethanol) for treating gas prior to storage.
I will use Seafoam for motors that are running like poorly, it has cleaned out the crap in the fuel system and the motors start running better after a day of usage. I do a Seafoam treatment in my boats (90hp & 250hp) once per year as a decarb/fuel system cleaner.
 
Don't use anything -my graduates need the work;-) JUST KIDDING !!!!!!!! As you see there is no one answer to this problem except in Wash D.C. (No I better not go there) Just this morning I had my class of first year students test samples of fuel for alchol and was plesently surprized, nothing over 11% and that may have been a test error. One guy had some 0% but he knew that it was from a no alchol pump. Personally I try to keep the fuel as fresh as possible and use Stabil. If a carb is still working but not well I use Seafoam as a detergent in a heavy dose. Off season I drain portable tanks and run built in ones below half. In the spring I mix in fresh for the built in tanks and have had no trouble. I also run a water seperator. Good Luck.
 
I use stabil- but after reading this, I am going to pick up some seafoam to try it. I also add some dry gas to my gas tanks for the small outboards when it starts to get cold- old Lake Champlain trick.
 
I'm on the boat everyday, EVERY tank of gas gets a blue Stabil/Startron cocktail, every now and then a tankful of Sea Foam mix. Probably not necessary as it's fresh gas, but since doing it this way I've had zero problems, and that motor is how I make a living.
I also have a Racor filter/water separator which has a higher micron filter then the spin on canisters.

Ethanol SUCKS.
 
I had problems with my 2004 2 stroke yamaha 150 for 2 years straight. It wouldnt idle or excellerate properly. I had a mechanic look at the motor and he said the carbs were good. He explained to me that it was just the ethenol and it is a common problem with carberated outboards due to phase separation and advised an additive. I tried a couple different addidtives including Star Tron and Stabil.. I then tried Sea Foam. After adding it, I took the boat for a 20 minute ride and by the time I returned the boat was running great. I expected this to be short lived, however it was not. I continued to add the sea foam throughout the season and the motor never missed a beat. It was as if I repowed my Parker. I would recommend anything else!!! Long story short, I use Sea Foam in all my equipment now....
 
I had problems with my 2004 2 stroke yamaha 150 for 2 years straight. It wouldnt idle or excellerate properly. I had a mechanic look at the motor and he said the carbs were good. He explained to me that it was just the ethenol and it is a common problem with carberated outboards due to phase separation and advised an additive. I tried a couple different addidtives including Star Tron and Stabil.. I then tried Sea Foam. After adding it, I took the boat for a 20 minute ride and by the time I returned the boat was running great. I expected this to be short lived, however it was not. I continued to add the sea foam throughout the season and the motor never missed a beat. It was as if I repowed my Parker. I would recommend anything else!!! Long story short, I use Sea Foam in all my equipment now....
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BTW the Parkers have had a lot of problems with their fuel tanks believe it had something to do with electrolics (sp) with some cheap welding material
 
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