Type of fuel for Johnson A J25RACCA?

[Jimiphone]

Gday to you all. I have a 1988 model Johnson outboard motor that I purchased recently off an old guy that told me it was a FOUR STROKE MOTOR. The model number he gave me is A J25 RACCA. I looked it up & it would seem that is correct. Australian, 25 hp, Rope start, 1988 model. Obviously I don't know a great deal about outboard motors, but have a fair understanding about engines in general. So basically I don't know weather to mix four stroke oil into the fuel, or 2 stroke oil into the fuel. It DOESN'T have an oil sump. I haven't heard of mixing four stroke oil into fuel before but have mixed plenty in the past for my mower etc. Either way, all I need to know is if this is actually a 2 STROKE MOTOR, or IS IT A FOUR STROKE MOTOR?? Any help would be really appreciated. Thanks in advance for anyone who can definitely tell me. Cheers.

[Tybo]

For a 1988, I could almost guarantee it is a two stroke. I had a '90 Johnson 30hp, roughly the same engine, and it was a two stroke, ran at 100:1 ratio, mixed into the fuel.

If you're unsure, start the engine. Can you hear it running, is it loud? Two stroke. Is it quiet? Four Stroke.

Undo the cowling, is there a dipstick? Four stroke.

Another thing is two strokes don't have valves on the cylinder head, so if the top of the cylinder just looks like a flat plate bolted on with your spark plug in the middle, then it is most definitely a two stroke.

Four stroke oil is thicker and designed to run through a sump. Two stroke oil is specifically designed to be thinner and therefore mix with fuel, also having additives so as not to create smoke when burnt. In other words, if it's a two stroke, use specific two stroke oil and mix into the fuel at a specific ratio.