1971 350 SL Electronic injection. Wet spark plugs

I have a 350 SL 1971 with electronic injection.
The engine vill not start. The spark plugs are very wet of gasoline so it will not ignite. If I block the fuel hose from the fuel pump with a vice grip. Take the spark plugs out and run the engines so the gas blow out of the sylinders. Put on dry sparkplugs.
The engines start and goes in 2 -3 second . If I open the vicegrip, and try to start again, it will not start. Spark plugs are wet. Someone know from experience what's wrong ?