'07 Mercury 9.9 Dies During Idle/Gas In Oil

[JDusza]

Hi.
I'm looking into an '07 9.9 that will eventually die is left at idle speed.
The engine starts fine with the high idle engaged. As the high idle lever is lowered into run position the engine starts to die. It can be saved by increasing the idle speed, opening the throttle butterfly.
To marginally improve the situation, I increased the idle speed via the idle speed adjustment screw.
The engine settles to an idle much better, but, if left to idle for several minutes it will eventually die again.
Restarts are tricky as the engine will easily flood.
Any ideas on how to keep it running at idle?
Thanks,
J

 

[JDusza]

9.9 Big Foot with Gasoline in Oil Sump

Hi.
I am looking at a 2006 Mercury F9.9ELB Big Foot 4-stroke s/n 0R153571, that is accumulating gasoline in the oil sump.
Additionally, it stalls at lengthy idle as mentioned in previous post.
Any ideas?
Can the fuel pump leak into the crankcase?
Thanks,
J

 

[GA_Boater]

You should look at the fuel pump for the fix to both problems.

 

[JDusza]

Thank you.
J

 

[JDusza]

Me again.
After changing the fuel pump the gasoline-in-the-crankcase problem appears to be fixed.**
The unit still suffers from stalling at extended idling. The stalling symptom is not as prevalent but it is still happening.
Restarts are hard after the stall and must be performed at high idle if not holding the throttle plate wide open. The engine will cough and sputter to life and eventually will catch up to the high idle speed and burn off all that is choking it.
So, the engine is flooding at extended high idle. How do I fix this on this carburetor? I see only an idle speed adjustment and a plunger to an accelerator pump(?).
Help is appreciated.
J

** interesting to see Mercury bit the big one on having a fuel pump mechanically actuated by breaching the crankcase. They eventually corrected the failed fuel pump membranes by water cooling the fuel pump .... ouch!