apart from the exhaust smoking and the spark plugs getting oiled and carboned up i dont think anything detrimental will happen ,the engine may cut out or be hard to start though . i used to allways put a tad extra oil in my fuel and never had any problems in fact i bought the engine new in 1976 and until i sold it last year apart from plugs and impellers and a waterpump housing it had never let me down and i used it on average about 30 hours per year .
Try not to leave it ticking over or running at slow speed/revs too long as the plugs could oil up and you'll need to whip them out and clean them to start it.
Other than that and a smoky exhaust it should be fine.
Extra oil will build up as carbon and become trapped behind the piston rings over time. They are then pressed outwards against the cylinder walls creating hot spots leading to the engine slowing down and stopping as aliminium from the piston is picked up and and spread around. Otherwise not to serious . Rogue wave has a Tohatsu 90 that suffered a similar fate though for a different reason if you want to see what it looks like.
. Rogue wave has a Tohatsu 90 that suffered a similar fate though for a different reason if you want to see what it looks like.
