Saito FA100 running problems

Re-visiting your original statement, 20% of most glow fuel mixes is oil, and practically none of this oil is expected to burn so you should expect to see a heap of clean oil coming out of the exhaust - if it is dirty it usually indicates a loose exhaust joint or something else aluminium in the engine is rubbing. It does sound like you are running too weak at the bottom end if the motor doesn't spool up quickly and cleanly.

The oil residue is clean with a redish colour. I have, since the original post, checked the valve clearances and the inlet did need some adjustment. Also I am using the last of a can of fuel which has got me wondering if it is has lost some of its properties, maybe worth checking the next time I run with a fresh can.

I have had similar isues with just one of my four strokes. Did did everything mechanically and got a new can of Contest 10 and solved the idling issue

Just managed to fire the saito up on the bench using new fuel and it ran sweet without any problems at all. The last of the fuel I’d been using before must have deteriorated and I can only assume that the onboard glow system I’d used previously had been giving it a great deal of assistance running. So at least I’ve learnt something, if an engine seems to be running rough, try new fuel first. Would have saved a lot of messing about. And, hopefully sharing this might help someone else in the future if they suffer similar.

Thanks for all of your input. Fingers crossed at the field hopefully tomorrow

Glad you have solved it. Glow plug is first check obviously, and if you have not fiddled with carb jets or at least if you have put them back to factory settings and start from there although usually only the main jet needs tweaking depending on temps and humidity. Then go for fuel I think that the fuel once opened loses it's kick due to being out in the sun's UV. I now surround my fuel can with insulation silver foil and had no problems since... Broke my heart having to dump half a can of fuel at £28 a gallon and buy some more but that is minor compared to going up the field and the flipping thing not running right. Been there and done that!

Yes very frustrating and fuel is expensive enough. Luckily was nearing the end of mine so not so bad.