I have 1979 4.5 hp merc. Ran good most of last summer. When it didn’t run good all I hade to do was squeeze the fuel bulb as it was running. It did this for a few fishing trips. Then it started running fine again. I thought maybe the fuel line hade gotten pinched or something with the connector for the fuel line was a miss. Now when I start it I chock till start let run turn chock off rpms go up motor dies. I can keep it running if I keep chocking. Thanx in advance