We have a 1987 Mariner 45hp outboard engine. We have spend almost $900 this year alone on servicing and parts. We started the engine the other day after it was serviced in April, engine started and idled for about 5 minutes then slowly quit. Any ideas on what could be causing this problem. Don't have much faith in the repair shop. After it was serviced in April we took it out and got stranded.... went back into the shop, they added more parts and said it is now working and has just done the same again. So frustrating 