I have a similar issue. My Volvo Penta 4.3 GL-EF once it runs works fine. But getting to start is a whole other story. I have had to top up the water/Fuel filter and add a bit of gas into the carb - starts up and runs fine. Reading thru some of the posts on this forum, and looking through the electrical drawing it seems to point to the connection ( Steering diode) that runs from the ignition switch. Since it runs fine once it is going ( power is now being supplied by the alternator). Would anyone happen to have any idea as to where in the harness these diodes are located?