What engine / model #s would be helpful. First guess is the ignition coil is on the way out- especially If you have a Tecumseh engine. Some Briggs have different issues that are more common to them.I like to cover my bases knowing the fuel is fresh, carb clean, fuel cap vents well, and has a new spark plug 1st. You could pop the air filter and give a shot of carb spray when it is in not starting mode and see if it wants to fire up when you pull it.

'Very similar mowers' Actually, not. The Platinum has the hi-dome deck, unique to the LB 'Insight' Series. The steel version on my LB 10684 has been a great mulcher. The LB uses a Tecumseh and the Toro a B&S with the same 6.75 torque rating. They both have 'Personal Pace' (LB calls it 'Sensa Speed'). Neither mower has a 'transmission' per se - the constantly-slipping drive belt and control mechanism is the 'transmission'. The box on the axle is a gear reduction and turns the axis of rotation to the axle, like the 'rear end' of a vehicle. The LB does use a different box than the Toro, and it doesn't have the greasable clutch housings at the rear wheels (these do not grease the wheels). In their advertising they claim it is a new-designed unit, so maybe it does eliminate the pull-back problems with Personal Pace. The hose port on the Toro is a gimmick. On mowers without it, you just direct the hose stream under the deck and it does the same thing. You have to tie down the bail to let it run while you hose it in either case unless you want to stand right behind it and get wet. I can't comment on the Toro's abilities, never having used one. Good luck on making your choice between these two fine premium mowers!

Probably you would use the green chute and side bag arrangement with this machine. Kits are usually available on ebay. Do not get the rear bag kit with the long black chute unless you know for sure it will work on your mower. Generally these are used on the offset-wheel decks with the open area behind the engine and special hole in the deck for the chute/bag support.

Thanks for all the responses. I'll google the suggestions. I still haven't found an exact fabric match for a lawnmower bag. I did get the bag from grasscatchersusa.com and it appears to be excellent quality. In the meantime I had an idea that has worked well. I went to a yard sale and bought a pile of several big heavy fabric duffle bags, backpacks, and suitcases. I hand sewed 2 of the suitcases together, cut a hole in the end of one and attached a fabric tube with a drawstring to attach it to the leaf vac. I sewed nylon webbing to them to hang them off the leaf vac handle. I cut a hole on the side of one and sewed a piece of shade clothe on to allow air to get out. So far so good, plus they hold more than the original bag, are easier to empty because the zipper on top opens nearly the entire bag. Best of all, it cost just $2 for the pile of old fabric suitcases, plus my time sewing it (about 3 hours). If I find a source for lawn mower bag fabric I'll post it. I haven't found even a universal bag, so I'm beginning to think the fabric might be proprietary. -hald