i have an old 40 seahorse johnson....i had it out 2 weeks ago for the firsttime this year and it ran fine except the key would not start the engine so i had to pull start it, butit ran fine. 2 weeks later my friend took it out and added 350ml of oil to 10 litres of gas.(wrong mix) not sureif this could be the reason. but he he couldn't get it to start. now i tryto pull start it and it started twice in about 40 tries but stalled after about 2 seconds, but it turns over every try. any suggestions?