99 25 marathon marriner wonbt keep prime

[Bob B]

"Got a good dose of wet fuel i

"Got a good dose of wet fuel in my '99 marathon 25 with a wmc 54 carb. Put a merc gasket kit in the cleaned carb and ran it on cleaned tank, line and new fuel. Will not hold prime and stalls after short run. If bulb is pumped on fuel line from tank it will keep going. Bought another diaphram for the fuel pump thinking it was perforated, but it did not help. When first cleaned, the float was closer to 13/16" height than the 1" merc recomends in the service manual. Set it both ways now and still no change in the fuel starve condition. Inlet seat looks good. Can run by pumping fuel line bulb every so often but not without. Am wondering about the fuel pump body now with the two metal reed type valves. Are the valves supposed to sit on the seats at rest on the bench if good or do they get sucked closed if they are a little high? I am rulling out the spring and plunger that push against the diaphram since they worked fine before the thing got fed on water. Should I be chasing the pump or the inlet passage for blockage? Ideas? Thank you in advance."

 

[Bob B]

Today put in a new inlet needl

Today put in a new inlet needle and a know good fuel pump body. Still loosing prime. Tank pickup screen is clean.

 

[Bob B]

"It turns out that the Maratho

"It turns out that the Marathon carb, wmc 54 uses a gasket with a slot instead of a hole for a pathway to get the vacum from the crankcase to the fuel pump. I installed the gasket in the kit with the hole only. Pictures of the part did not show it well and when I lined up the gasket on the carb back it looked good. No air from the crankcase was getting by without the off center slot and so a no pump condition was created."