classic motorcycle forum

All I can say is your fuel must go off mighty quick.....I buy 5 gallon drum of petrol for the mower etc when its cheapest ,about once every six months,dont have the lid tight so the drum doesnt bang with temp changes,and Ive never seen the slightest deterioration of the fuel......Mind ,I never buy alcohol fuel,cause the chainsaw specifically warns about it,and in any case alcohol fuel is actually more expensive than straight unleaded......by about 4 c per litre,even tho the pump price is 2c less /l.(less energy content)......I might add .I can clearly smell the alcohol in 10%,and also the exhaust smell of the mower is obvious with alcohol,so there is no chance of having it by mistake......Not that Im doing a lot of mowing with the drought......with bikes ,I always drain and remove the tank if Im not using the bike regularly,and swill out with 2 stroke mix.This stops the rust forming around the inside near the cap.

Yes ,its a Matchless G3L....you have reversed the pictures.

The motor is already mounted on a stand......I would hook up an electric motor with a V belt drive to the outside of the flywheel ,motor the little engine at about 500 rpm,and experiment with increasing the fuel supply from nil to full on via a tap in a mower tank.You could also rotate the terrot with a big electric drill ,but the drills generally have too much starting torque ..........never the less ,this is how I start my 8hp B&S on a rider mower ,since the recoil  busted many years ago.This engine was also impossible to start manually,due to advanced wear in the carb,but a few seconds with the drill ,and we re off mowing.

If you want the easy way ,get your cases wet bed blasted......and make sure the operator is using new bead.......IMHO its best to find someone with both wet and dry processes ....the worn wet bead can then be used up in the dry blasting process,rather than left in the wet machine until its dust.......A blast with new bead will produce a lovely dull sheen,obviously not OEM,but very nice to look at...

You mention black staining in the drain fuel......it does sound like the seals are dissolving.This would not surprise me ,as modern unleaded does have many constituents in common with  older type paint thinners.Not running on aerostart is pretty indicative ,IMHO.My old chainsaws are impossible to start after sitting for years,but a good spray of aerostart ,they fire up ,and the added suction pulls any oil blocking the jets out,and away they go in a cloud of smoke....The newer saw I bought to compensate for my advancing years had a very big warning about fuel,no alcohol,and be sure to drain the tank and then run the motor dry while still hot,no matter what fuel is used......I know of an Ariel Leader engine rebuild where new seals were found to have cracked after the performance went right off in a short time...........but didnt the Terrot have metal face seals?.like a Scott.

All this reminds me of a scene some sixty years ago ,me and my brother used to go round a friends place ,and  tinker with a little non descript 100cc bike ,not a Villiers ,dunno what it was........anyway ,we would get it going and  run it around the streets ........only for  a while ,because the flywheel keyway was flogged half way round the shaft,and when the timing shifted it would stop....till next time..........I had a monumental buster on it ,onlookers say it cartwheeled,all I know is I ripped the insides out of both knees,and skinned my arms very thoroughly...........I have hated little two stroke bikes ever since.

mention of difficult hot start....... a sure sign of mag windings breaking down......a mini capacitor(aka Thorspark) will restore spark for a time ,and for the price is worth trying.........You should note that mag repairers specifically state that any supressed components in the ignition void the warranty on rewinds.....because these supressed components double the voltage at the mag coil and cause insulation failure.