I've found the best way to prime an '87 300D is to pull the fuel hose off the IP, and use a vacuum pump to pull the fuel all the way up to that point. stick the hose back on the IP and it should be only minimal cranking before it starts. That saves your battery, starter, and IP from excessive wear and tear.

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1987 Mercedes 300D ~200K (Greasecar & Biodiesel)
1993 Ford F-250 7.3 IDI diesel 165K (Biodiesel)
1996 Thomas/International Bus with DT466 engine