that looks an awful lot like the two Green Machine weedie's I have and the one Stihl FS78 or whatever it is, and with the research I did on the Stihl it was a 25, and since the green machine weedies look the same (down to the barrel style carb and the spark plug position) I'd assume they're 25's too. I haven't gotten the green machines going as both have either a broken or missing fuel tank, and the stihl only runs if you hold the primer button down... (has brand new carb kit).

I haven't torn into the green machines (have $5 into the two...) but the Stihl has points ignition... if you pull off the pull starter you will probably see the parts as the front just has the fan on it