I've been using Omega 15% in all my 2 stroke engines. I've recently purchased a a O.S. and Saito 4 Stroke engine. Is it ok to continue with Omega 15% fuel with the 4 stroke?

It will be fine.

You will find that there is a big debate about fuel but remember it is mainly subjective.

"You will find that there is a big debate about fuel but remember it is mainly subjective."

Except for oil content. Two stroke fuel has less oil than 4 stroke fuel, and a 4 stroke will suffer.

Les

I think you mean 4 stroke fuel has less oil than 2 stroke fuel.

Originally Posted by Kit_Builder

It will be fine.

You will find that there is a big debate about fuel but remember it is mainly subjective.

Agreed, it is mainly subjective.

The oil content is not a critical matter. Many, particularly Europeans use as little as 12% oil and have no complaints about the engine life.

Typically in America we have 17% to 20% oil and some fuel is available with some castor oil added. In the old days of 1950s and 60s some engine used all castor because of the metals used for engine fabrication.

I have been using Morgan Cool Power in both 2 and 4 strokes without issues. The label shows 10% and 15% but does not say if that is oil or nitro content. I assume it is nitro. Some with 10% nitro and some with 15% nitro. It says on the label "do not use after run oil" as it contains rust inhibitors.

If my interpretation is correct and the % shown is nitro then there is no indication of the oil content but it does say it is "total synthetic".

Zor

i have used 15% in my 4 strokes no prob.....

"I think you mean 4 stroke fuel has less oil than 2 stroke fuel."

No. 4 stroke fuel has more oil than two stroke, because the 4 stroke does not flow the fuel through the whole engine the way a 2 stroke does.

Les

Lol

2x lol

If you two are laughing at me, laugh away. I will just consider the source. For many, many years, when fuel was not so readily available, I bought my nitro by the 5 gallon container from a shop that supplied dragsters and such, and castor oil from a commercial supplier; mixed up, and sold fuel to the surrounding fliers to pay for my own addiction, so I did have to do more than just a little research into the subject.

I one were to make a CASUAL examination of two stroke vs four stroke, one would realize that in a two stroke the mixture is introduced into the crankcase, and then disbursed into the engine. In a four stroke, the mixture is introduced into the head (through the valves), and the only lower engine oiling is by whatever bypass there is in the engine.

Les

doesnt matter anymore on any reasonable fuel.
in the early 90's (may have been late 80's IDR) "4-stroke" fuels came out. instead of 20%'ish castor like normal fuel, they used synthetic blends to drop the oil content in the 15-17.5% range.

if youll look on any bottle of normal old glow fuel made in the last 10-15 years in the USA. youll notice most normal 2-stroke fuel is running synthetic blends around 17% oil.


oil content is pretty close either way. dont let them get lean and youll be fine.

I have a blending question. I have a gallon of Byron Gen2 Race 2000 20% nitro, 12% lubrication. I know the lube is a 50/50 blend synthetic/castor. I want to bump the oil content up to 25% using sig castor. This gives me a nitro content of about 17%. My question is this: Will this blend work good for ok cub, cox .049 engines? Will the synthetic have an adverse effect? Is the nitro content sufficient?

"My question is this: Will this blend work good for ok cub, cox .049 engines?"

I would not expect it to. Cox fuel was, as I recall, high nitro; to develop some amount of power; and, low oil; so that the reed would not get gummed up.

Les

Originally Posted by LesUyeda

"My question is this: Will this blend work good for ok cub, cox .049 engines?"

I would not expect it to. Cox fuel was, as I recall, high nitro; to develop some amount of power; and, low oil; so that the reed would not get gummed up.

Les

http://coxengines.ca/files/FG.pdf

The only warning I heard about 4-stroke fuel was that they can't tolerate too much castor oil, because it can gum-up the valves.

The fuel I used in both my 2-stroke and 4-stroke OS engines (before I went electric) contained 9% synthetic oil and 6% castor oil, and 10% nitro. Never had any wear or running problems.