I have a newly built float plane which I installed an OS 91 FS motor. I fly the plane at my lake and I am a little bit concerned about the noise it makes when flying - I don't want the neighbours to get annoyed.

Is there any other muffler/silencer solutions for 4 stroke engines that can make them run more quietly? If so how might I get one and will they sacrifice engine performance?

I have a Seamaster which has an OS 46 FX and I put a super silencer exhaust on it which makes it a lot quieter.

I know this is not exactly a seaplane related question, but I would suspect that others flying on water would have had this issue as well.

Thanks.