Ran my OA-55 last summer. Working on a You Tube video. It will have some of what was posted here. The link is to what will be the ending of that video. This is a new camera. I dropped my other one and chipped the lens. They come with a waterproof case so I kept this camera in it to protect it. Well that seems to muffle the sound some. That and the times I have the tiller resting on my camera mount distorts the audio. Later on in the summer I started getting some pre-ignition in the starboard cylinder when starting and trying to run slow. I’ll post some pictures of what I found when I get a chance.

Video link https://youtu.be/-V-pMaYLdTk  

In my attempts to try using a ball bearing the straighten these air horns, I have discovered a major problem. This socket is exactly the right size to remove dents from the straight part of the air horn. It just fits. Its outside dia. is about 0.800. The nearest fraction would be 51/64th. (0.796). A bearing that size would probably straighten the bend in the air horn. I would also need a couple smaller bearings to work up to the 51/64th bearing. The problem is finding a 51/64th (0.796 or 20.23mm) ball bearing. I have spent some time looking. I thought I had found one but my head flipped the 15 around to 51 and it was awhile before I realized it wasn’t what I thought it was. Don’t know what I would have done with 300 of them.