Voila!
Replacement part suitable for the following makes & models;HondaHF2113, HF2114, HF2213, HF2216, HF2218, HF2315, HF2415, HF2417, HF2620,Mountfield1228H - 13-2642-17, 13-2642-14, 13-2642-15, 13-2642-16, 20131228M - 13-2641-17, 13-2641-14, 13-2641-15, 13-2641-161235M - 13-2687-121236M -...
www.gardenhirespares.co.uk
Unfortunately, no way of getting into these to replace the bearing alone.......unlike the other pulleys on these machines.
Do watch for the bracket orientation as you are working under the machine - it's dead easy to let it face the wrong way!
As for the starting, the spark at the plug is produced by the magneto underneath the engine flywheel, and the faster it spins, the better the spark. The machine battery is only used to operate the starter motor and lights etc.
The ignition switch only controls the starter and the engine cut off - that's a black wire that exits the engine, and if grounded the engine stops.
Now then - if the battery is slightly below par, maybe the engine isn't spinning as fast as it might, but by releasing the ignition key the engine gets that slight impetus more to fire it into life....the starter is in effect, slowing the engine down! That's my theory anyway, which may be nonsense but my machine did the same. Looking at the price of a new battery though, I'd be inclined to put up with it!
As I said, only my theory.
The only issues I have with these machines is grass packing around the cylinder fins at the bottom of the engine cover, and the rocker drive pedal is hopeless to grease without removing the grass chute...other than that, with care they go on a long time but do keep the transmission oil visible in the reservoir.
Regards
John