2006 Mercury 4-stroke EFI 90hp stalls at idle/no wake

[snichols001]

Serial # 1B797016
194 hours
Thanks for looking, here is my situation:
Preseason:

• New impeller
• Oil change
• New fuel/water separator
• New high and low pressure fuel filters
• New air filter
• Fresh gas

1st use:

• Higher RPMs (2k-4k) ran OK, every few minutes, would drop 200 RPM and recover
• Idle/no wake 700-1500 RPM, after ~10 minutes, shake and stall. Would restart after a few minutes.

Troubleshooting

• Replaced plugs and pencil coils, now runs fine in high RPM range (no surge/RPM loss). Good acceleration, WOT at 5600 RPM.
• Fuel pressure 40-45psi, during shake/stall sequence drops to 20, then 0
• Connected Vessel View, oil pressure, water temp, voltage look good
• No codes in Vessel View
• Removed and cleaned FSM
• Bench tested both high pressure and lift pumps - both seem OK
• Float switch had no continuity - replaced it

Still stalling at low RPM
It's clear that the FSM is emptying. If I pump the primer 10-20 times when it starts to shake and stall, the engine recovers.
Where do I look next? IAC valve, fuel regulator?

Thank you

 

[snichols001]

Serial # 1B797016
194 hours
Thanks for looking, here is my situation:
Preseason:

• New impeller
• Oil change
• New fuel/water separator
• New high and low pressure fuel filters
• New air filter
• Fresh gas

1st use:

• Higher RPMs (2k-4k) ran OK, every few minutes, would drop 200 RPM and recover
• Idle/no wake 700-1500 RPM, after ~10 minutes, shake and stall. Would restart after a few minutes.

Troubleshooting

• Replaced plugs and pencil coils, now runs fine in high RPM range (no surge/RPM loss). Good acceleration, WOT at 5600 RPM.
• Fuel pressure 40-45psi, during shake/stall sequence drops to 20, then 0
• Connected Vessel View, oil pressure, water temp, voltage look good
• No codes in Vessel View
• Removed and cleaned FSM
• Bench tested both high pressure and lift pumps - both seem OK
• Float switch had no continuity - replaced it

Still stalling at low RPM
It's clear that the FSM is emptying. If I pump the primer 10-20 times when it starts to shake and stall, the engine recovers.
Where do I look next? IAC valve, fuel regulator?

Thank you

Hello,

ve 2 observations:
1) Engine continued to intermittently ran rough at idle
2) Engine still stalled at low RPM, but it took longer for it to reach the point of stalling

After burning through the second tank, I noticed that the fuel connector on the cowling side looked wet.
This connector only had a zip tie, so I added a clamp.

After adding the clamp (this may be a coincidence) low idle seems to be OK - no stalling, so far.
Now, when I start the engine, I get a fuel vent switch error 1112-23.

Thank you for your help!

Steve