My '76 300d (w115) has decided that starting is a merely optional activity. Basically I have been doing some experiments with a two-tank WVO setup. Yesterday I hadd been running on WVO for a testdrive and it was going fine until I start heading back and I push the switch to put it back on diesel. In a very short time the engine starts missing, power drops, and it dies. Luckily I'm at the top of the hill from home and was able to coast back down into the driveway. I check the fuel lines and the diesel line is kinked. Fixed that problem, try to start: no go. Open the fuel-filter housing and it's basically empty. Filled that with fresh diesel and operated the hand pump: no go. I think it sucked air into the injection pump but truthfully I don't know, need help from forum gods.

mac2,

Pump the primer pump rapidly about 50 times. Then try to start engine.

If you notice a leak from the primer pump, it may be leaking air into the system and needs to be replaced.

P E H

also be pacient, it takes time to bleed air from the Injection pump.

After priming as much a humanly possible with the primer pump (PEH- says 50 times, which sounds like a good number) Just crank for no longer than 15 seconds at a time with no shorter than 30 seconds in between cranks. Do this until it starts which should be within 5 minutes of total crank time.