'80 450SL stored 7 yr with ethanol gas in tank. Starts with ether or gas poured into top of injection sytem but won't continue to run on it's own. Mechanic says ethanol absorbed water & resulting corrosion in tank, pump, lines, filters etc. need replaced as too hard to repair. Like to get running with separate fuel system too be sure not other car problems before $3k replacing these parts. Assume can run with small tank, electric pump & lines direct to injector system? If so what PSI should pump be set?