Gasoline and Additive Information needed

[badcarma58]

I am new to the outboard motor arena. I have previousely been a Mercruiser I/O user.

I just bought a 2007 Mercruiser 150hp 2 stroke V6.

What is the best gasoline to use? 87 or 89 octane from the car gas station? I know most boat dock gas is 89 octane with valve tech added already.

Also, if I use gas station gasoline, do I need to put additives into the tank as well. I used Valve Tech with my I/O, but that was with a 4 stroke motor.

Do I need to valve tech additive, or ethanol additives, when I fuel up, for my 2 stroke motor since oil is added to the gas before it goes into the engine for combustion anyway?

 

[ondarvr]

Re: Gasoline and Additive Information needed

The truth is you don't need to use any additives on a daily basis unless it makes you feel better, an occasional product to remove carbon and clean things up doesn't hurt, so doing it every now and then may help.

There are those that use some type of product in every tank, others use nothing, they both report very few problems, so you take it from there.

 

[Home Cookin']

Re: Gasoline and Additive Information needed

use the cheapest gasoline you can find and invest the savings in liquid assets (beer).

Additives are important in most parts of the country if you use E10 if the gas sits for a month or more, not if you use it all up--not likely with a big motor. Humidity and temperature swings are a big cause of E10 problems.

A water seperater is crucial.

I use ringfree and startron in a relatively new carbed Yam 150. Startron or stabil in an old Johnson 70 and old Yam 50 (both carbed). However on those two, I get non-ethanol gas. The old 70, however, often sits in temperate and humid conditions for 3 months at a time.

 

[Chris1956]

Re: Gasoline and Additive Information needed

IMHO, Startron is snake-oil. I use a fuel stabilizer over our 6-7 month off-season. The OPs motor was designed to run on E10, so no issues there. Use 87 Octane. There is no need to use any higher octane stuff.

 

[Mad Dave]

Re: Gasoline and Additive Information needed

Just for the sake of discussion, why is Startron snakeoil? What brand of stabilizer do you recommend?

 

[Chris1956]

Re: Gasoline and Additive Information needed

Dave, Startron makes several claims that I simply do not believe. Here are the claims that make no sense. From the Startron web site:

Star Tron? cleans the entire fuel delivery system, removing performance robbing gum and varnish deposits while modifying how gas and diesel burn, this results in more complete and uniform combustion and therefore better fuel economy.

"Modifies how gas and diesel burn" - WTF, how does it do that?

With the removal of harmful engine deposits and an increase in combustion efficiency, exhaust emissions are greatly reduced. This results in cleaner air and cleaner boat transoms as black exhaust smoke is noticeably reduced.

Black Soot would only be noticable is you had a bad mixture, defective carbs etc. How does Startron fix that?

Carbon deposit formation is a byproduct of unburned fuel in the combustion process. Star Tron's enzymes will break down and disperse these deposits restoring engine performance as it also modifies the fuel to prevent future carbon deposits.

"modifies the fuel to prevent future carbon deposits", again, how does it do that?

Ethanol / E10 fuels increase the amounts of water and sludge in your fuel tank.
Star Tron breaks down this excess water and sludge to sub-micron size allowing it to be safely burned away during normal engine operation.
Therefore Star Tron prevents phase separation and fuel gelling, eliminating ethanol fuel problems.

"Star Tron breaks down this excess water and sludge to sub-micron size allowing it to be safely burned away during normal engine operation" So it breaks down sludge and burns it? Sludge could be sand, dirt or other inorganic material. Makes no sense.

Just my opinion. I do not recommend any particular fuel product. I use a fuel stabilizer over the off season only, but never flew it off against untreated gas.

 

[Scubaslife]

Re: Gasoline and Additive Information needed

Seafoam & Stabil seem to get the most recommendations from the mechanics I've spoken with.

 

[JoLin]

Re: Gasoline and Additive Information needed

Seafoam & Stabil seem to get the most recommendations from the mechanics I've spoken with.

Those are what I use, but only 'on occasion'. If you're using up gasoline regularly you really don't need anything at all. I use Sta-bil before winter layup, only because the boat will sit idle for 6-7 months.

 

[JB]

Re: Gasoline and Additive Information needed

I just bought a 2007 Mercruiser 150hp 2 stroke V6.

No such critter, Badcarma. I am sure it is a Mercury outboard. Mercruiser does not make outboards.