I had repeated trouble with tohatsu 6hp starting,stoping, not maintaning idle. All traced to fuel line connection fitting at motor. They recomend disconnecting fuel line after use but frequent on/off can and will damage "o" ring in connector causing air leak and fuel starvation. When pumping primer if anf fuel is seen at motor connection O ring is out of place,pinched, or nicked. I now keep a few spare connectors (wall mart 4 bucks) Prior to this I would lose prime and had to frequently squeeze prime bulb. When this situation arose I knew my engine would not keep running. With good connector, bulb stays hard (under pressure) after weeks of not using. cheers frank