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1973 Merc 500 - Starts, dies on idle after running

Sctrjother

New member
So, I have the 1973 Merc 500 that I have done a lot of work on; rebuilt carbs (new floats, pin does close correctly), replaced all wiring harness and spark plugs/wires, impeller, starter, fuel pump gaskets and lines, added a fuel/water filter/separator and a couple other things I think that don’t come to mind. If left sitting alone for a while I can prime the bulb and it gets fairly firm. Engine fires right up and can stay on idle for some time. I let it run for 30 minutes (purred like an angry kitten, but nothing I would not expect here) to see how it ran (on hose) then brought back to idle. Died right away. Let sit for a bit, could start but not stay running in idle position, but in minor throttle position, started and stayed running. I let sit for a bit and tried to primer bulb. Not firm at all. Primed fuel for a bit and the bulb never got firm again and I could not get engine to stay running longer than 2-3 seconds in idle. Any ideas?
 
Possible fuel restriction at the gas tank. Or the primer bulb is no good. Try holding the Primer bulb so that the arrow on the bulb points towards the ground and prime it
 
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