We have been having problems with our Johnson 50 acting up at low speed or idle. Motor will almost die out and then come back. After a couple of times of doing this, it will die unless the gas line bulb is pumped. At high speed - no problem. Coming back into the "No Wake" zone - dies out and then revs back up, etc. unless fuel bulb is pumped. Have changed fuel filter, spark plugs and fuel line and bulb. At low RPM, oil light and alarm will sometimes light up and sound off. Any suggestions???