After a couple of days trying to get my B5100E running after the winter layup I have finally discovered the problem and thought I would offer it to the forum. I treated it to a new battery since the old one wasn't holding a charge and she fired up pretty quick. Rode along a few hundred yards to fit the tiller to do some work and she wouldn't restart! Thinking it was still a battery issue I dragged out another much larger battery and tried that, and then heavy jump leads from my van with the engine running. All I would get is a partial fire up and a lot of smoke. It seemed to start but then starve of fuel and then just die. Then I read three or four threads on the forum about hard starting and how to bleed the fuel system and tried everything but still no luck. Then today I was trying again and happened to notice that while it was struggling to fire up one of the pulleys wasn't turning. The fan belt tensioner/idler pulley was stuck. 
The bearing was completely solid. So I replaced the bearing and she started first pull. It seems it wasn't a fuel issue at all but simply the seized bearing was creating so much drag that it was preventing the starter from turning fast enough and then the poor little 2 cylinder couldn't get spinning hard enough to get off idle. Has anyone ever had that happen? Weird but true!
The bearing was completely solid. So I replaced the bearing and she started first pull. It seems it wasn't a fuel issue at all but simply the seized bearing was creating so much drag that it was preventing the starter from turning fast enough and then the poor little 2 cylinder couldn't get spinning hard enough to get off idle. Has anyone ever had that happen? Weird but true! 
