I've recently bought a SAITO FG-21 as my first gas engine and read the instructions meticulously. Then I was very excited to have it start up and everything first go! Did my break-in and everything (never flown)! Only to accidently noticed I have ran in using the incorrect oil ratio T_T. I ran it in with a 40:1 as oppose to the 20:1 indicated by the manual.

My question is, how stuff is my engine? Is there anything I can do to "fix it"? Or just keep flying it until it gives up and get a new one?

Thanks in advance

I have similar concerns about an O.S. 46AX engine I recently started breaking in, worried I may have run it too lean. Meaning not enough oil. Might be similar to your case I guess, even though this is a methanol engine running on 18% oil.

According to the instruction manual, the symptoms can then be that the engine drops in RPM when it gets hot, because it is still too "tight" (not finished breaking in). The instructions said to then run the engine rich on the next flight instead. Based on this, I would guess there's a chance the engine will be fine, it just isn't finished broken in yet. So maybe it would be good to re-do some of the break in runs with the higher oil mixture. But I'm no expert and don't have any other experience with this, just mentioning it in case it's relevant.

In both cases, if the engine wasn't run lean or hot, you should be OK unless you are the kind of people that insist on running the engine for endless hours for break in. On the 46, they are very forgiving engines that require minimal if any break in. On the Saito, the main area of concern would be the plain aluminum, unbushed rod ends. If the engine turns over freely and without excessive rod end play, you should be OK.