Mercury 115 efi 4-stroke (2007) fuel problems (fixed)

[cordorascat]

This is not a question, more of a statement of my own experience with my Merc 115 efi 4-stroke. This may help someone in the future.

Thanks to member PontoonboatFun for his post date 4 Aug 2012
Engine was running real rough and spewing fuel from the air intake and after doing all the usual checks including fuel pipes, fuel filters, plugs, pin coils, injectors and air filter I came across the above post which mentioned fuel pressure regulator vacuum hose. Of course the fuel pressure regulator is inside the fuel supply module which has 8 bolts holding it together. I carefully took the module apart and found to my relief that the vacuum hose had a 1 inch split along its length. One new hose later and she fired up perfectly without missing a beat!!

Just a simple fix, it's a pity that the hose isn't more accessible

 

[Timestep]

Re: Mercury 115 efi 4-stroke (2007) fuel problems (fixed)

Great info, many thanks.

Dave

 

[mcsmith]

I just had this very same thing happen on my 2007 outboard. Kind of a PITA to get at it, but the problem is now fixed. Really fouled out the plugs so I also replaced those, Spoke with my local boat mechanic to see what he recommended for cleaning the soot out of the cylinders, and he said to use Engine Tuner sprayed into the air intake, and let it sit over night, then run it hard the next day. Here is a link to a service bulletin that covers this split hose issue, and other fuel module trouble shooting!:
http://www.marinemechanic.com/merc/...oard/FuelSupplyModule(FSM)Troubleshooting.pdf

 

[rebmo]

I know it's 4 years later but think its important to add to the statistics here.

My 2006 115hp Merc 4-stroke had the same thing happen. The cheap thin Merc OEM hose ruptures and can do a lot of damage to starters, batteries running down, flywheel gears getting ground by the starter as the lower cylinder hydra locks. Mercury seems real quite about addressing this major design fail. It locked up my motor since the lower cylinder filled with fuel and killed the starter cracking the top cover. I drained all the fuel from the lower cylinder. I'm going to use some high pressure fuel line (ethanol tolerant) to correct the design flaw in the fuel regulator instead of the little flimsy plastic OEM vacuum hose for $18-20, really?

At the same time I went through this I discovered the air filter disintegration and a small part of the foam missing. Glad I caught this. It's another Merc screw up. The foam disintegrates and gets sucked into the motor. Of course Mercury will sell you a new improved filter for $80 plus (air filter? really).