Logo
FULL SITE MENU

2012 Mercury 90hp stalls after running 5-10 minutes

C

coop0775

New member
I have a 2012 Mer. 90hp 4-stroke. It starts immediately and runs great but after about 5-10 minutes it starts running rough then shuts down. It'll immediately start back up but runs very rough. If I let it sit for 10-15 minutes it'll start back and run great then does the same thing. You can hear a slight light whistling sound coming from the air intake start and then seconds later is when the trouble starts. The sound gets louder as the motor gets worse. I've changed the fuel filters and the lift pump but still having the problem. The boat did sit up for a couple years without being started but after swapping out the battery it started right up and ran on the water fine for several hours before the problem started. I'm at a complete loss.
 
Try loosening the gas cap to allow air in, if the tank vent is restricted the fuel supply will stop as soon as the tank vacuum is the same as the fuel pumps pull. I also hear that the internal lining of fuel hoses can come loose and restrict fuel flow.
 
Last edited:
coop0775 said:
I have a 2012 Mer. 90hp 4-stroke. It starts immediately and runs great but after about 5-10 minutes it starts running rough then shuts down. It'll immediately start back up but runs very rough. If I let it sit for 10-15 minutes it'll start back and run great then does the same thing. You can hear a slight light whistling sound coming from the air intake start and then seconds later is when the trouble starts. The sound gets louder as the motor gets worse. I've changed the fuel filters and the lift pump but still having the problem. The boat did sit up for a couple years without being started but after swapping out the battery it started right up and ran on the water fine for several hours before the problem started. I'm at a complete loss.
Click to expand...
Did you ever solve this issue? Im having the identical symptom with my 90 hp Mercury four stroke outboard.
 
What happened to the old gas? Drained it and filled with fresh fuel, or left it in and added new fuel to it? Whistling and then problems sounds to me like a foreign object is vibrating as the intake air passes over it. A 2012 engine is 14 years old. Plenty of time for hoses to deteriorate.

For lack of a better solution, remove your fuel filter and cut it open. Anything of interest inside?
 
I have a 2012 Bigfoot EFI 60hp and it does this as well. Has been to the marina 3 times and they are baffled. Replaced fuel lines, fuel filter and pressure regulator. Does it with the gas cap vent open or closed, so I don't think it is vacuum. About to go back to marina and pick up a portab;e gas can to make sure it is not the tank or the gas. Anyone have other suggestions ?
 
jack63ss said:
I have a 2012 Bigfoot EFI 60hp and it does this as well. Has been to the marina 3 times and they are baffled. Replaced fuel lines, fuel filter and pressure regulator. Does it with the gas cap vent open or closed, so I don't think it is vacuum. About to go back to marina and pick up a portab;e gas can to make sure it is not the tank or the gas. Anyone have other suggestions ?
Click to expand...
Cut the fuel filter open and tell us what you find. A portable tank with fresh gas is a good idea. You might want to purchase your tank and gas elsewhere just to eliminate those possibly becoming suspect......for whatever reason.
 
Back
Top