fuel additive and outboard engines

[OttawaRiver]

I am wondering, does anyone use fuel additive to clean their outboard engines once a year?

 

[triumphrick]

Re: fuel additive and outboard engines

You bet. There are some really good posts using sea foam. If you use the search function and enter it you will find a procedure using a portable tank and only a couple gallons of gas mixed with about 1/2 can of seafoam. The rest is sprayed slowly into the carbs with the motor running on the enriched mixture. Also a few ounces are poured into each cylinder and left to sit awhile to clean more carbon...makes for some good reading! Good luck!

 

[OttawaRiver]

Re: fuel additive and outboard engines

I found it

this is the method i have used for years.

Decarb, take a can of seafoam put 3/4 of it in the gas tank, with only 1 gallon of premixed gas. put the rest in a spray bottle. start the engine, and let it come up to temperature. then remove plugs, and them some real good shot of seafoam into the cylinders, replace plugs, let sit 15 minutes. restart, and spray the rest of the seafoam into the carbs, so the the motor almost stalls, wait and repeat until the seafoam is gone.then take for a wide open spin. then put in new plugs, ad premixed gas to the tank, and take it for a wide open throttle spin. it is going to smoke like a house on fire, during this process.

afterwards compression.recheck

Usually, I use Champion Fuel Injector Cleaner because they don't includes octane boost additive (my Yamaha engine doesn't perform well on high octane).

I will try Seafoam this year and post the result!

 

[coolguy147]

Re: fuel additive and outboard engines

whats happens when u put octane booster in a older motor?

 

[OttawaRiver]

Re: fuel additive and outboard engines

Well, when I put 89 octane in my 1992 Yamaha 2-stroke, I can't go higher than 4000rpm at WOT.
With octane booster, it's even worst : the motor doesn't idle well and it's hard to start the engine!

 

[coolguy147]

Re: fuel additive and outboard engines

lol ok but u know best way to get perforamnce is to make sure ur motor is proped correctly

 

[Silvertip]

Re: fuel additive and outboard engines

Using a fuel additive is not just a once a year deal and it depends on what you are trying to accomplish. Decarb can be done once a year but that should not be necessary. Adding SeaFoam (or your additive of choice) to each tank of fuel keeps the fuel system clean. Adding SeaFoam or Stabil at the end of the season keeps the fuel from souring during long periods of storage. So the answer to your question is YES -- but many of us use it regularly, not just once a year.

 

[JUSTINTIME]

Re: fuel additive and outboard engines

if you run top tier fuel, just use a stabilizer

 

[tashasdaddy]

Re: fuel additive and outboard engines

octane boost. most motors are designed to run on 87 octane, lead free gas. even the 1950's, ran better on what was called white gas, lead free. adding octane boost is a total waste of $$ can cause the motor to predetonate. possibly burning a piston.

 

[pvanv]

Re: fuel additive and outboard engines

TD, I don't understand. How would raising the octane cause detonation or preignition? Slowing the combustion (raising octane) should do the opposite.

Not that I find any need to waste $$ on octane boost. I don't. But I am wondering about your statement...

 

[Randybeall]

Re: fuel additive and outboard engines

A couple of misstatements in this discussion. On a two stroke engine even using TopTier fuel is not enough. Additives can clean the oil residue from the oil mix and additional carbon it causes which pump gas is not designed to do. Higher octane fuel will not cause predetonation or piston burning. It can however cause engine damage due to over heat of the exhaust passages. That can cause galling in the exaust port area and ruin pistons. If compression is raised the use of higher octane fuel can allow the production of higher horsepower but at the risk of high piston and combuston chamber temps. Both will eventually cause piston failure. Two stroke boat engines will give better overall long term performance with the use of an engine cleaning additive to all fuel used.

 

[Silvertip]

Re: fuel additive and outboard engines

You are asking about the "Decarb Procedure" and on two strokes it is a good idea. When you are done, continue to use SeaFoam or any other fuel system conditioner (Yamaha sells a good product) in each tank of fuel to keep the fuel system clean and help reduce carbon build up.