When Tammy Norie’s original engine broke, I bought a second hand Honda BF5 from Seamark Nunn in Felixstowe. Unfortunately, its recoil starter broke almost immediately, stripping the teeth from the starter sprocket.
I bought a new sprocket, but that jammed during my messing around in strong winds off The Naze and I had to dismantle it and use the emergency starting cord.
I’ve been using the starting cord ever since, and the engine has been fine in all other ways. But I don’t like running it with the cover off. There’s a chance of a rope or clothing getting snagged in the flywheel.
Seamark Nunn offered to take a look at the engine under guarantee, and I finally had a chance to take the engine to them yesterday (2014-09-10). Josh, their engineer, immediately helped me diagnose the problem by pulling out a similar engine and finding a diagram from the service manual.
I thought perhaps something was bent out of shape, because my sprocket teeth didn’t engage very deeply with those on the flywheel, but Josh pointed out that my fixed cap (part 9 on the diagram) and split pin (part 7) weren’t locked together in the same way as on the other engine, and that this would mean that the sprocket wouldn’t drop out of the way of the flywheel when the engine started. That would account for the teeth getting stripped: when the engine fired up it would push very hard on the sprocket.
I looked at the other engine and noticed that I had a piece missing.
There’s a large plastic washer (part 11) that spaces out the sprocket (part 4) from the recoil assembly (part 3). I’m certain that my engine never had one of these, and I did notice some home-made plastic spacers that I found suspicious. I reckon that the original owner lost his washer and then attempted a bodge. The result is that the split pin is too low and falls out of position beneath the cap. You can see it escaping in this video.
Josh found a spare washer and a spare sprocket. We put everything together and things worked much better. I might also bend the split pin slightly to make double sure that it can’t escape.
I recommend Seamark Nunn, who have been friendly, helpful, efficient, and professional.
I also had a great chat with Josh, who is restoring a Cornish gaff ketch and has plans for a six-year circumnavigation. If he starts a blog himself I’ll link it from here. She looks lovely.