2009 Mercury 90elpt s/n 1D738278 runs 20 mins and dies

[57slab]

Regularly would die in middle of lake, after an hour wait, run great all day. Authorized mechanic serviced August 2011, he ran 4 miles up lake and back no problem found. Next time out, week later, had to be towed in. Stored since August 2011. New remote tank, fuel lines, water pump impeller, fuel filters pass fuel easily. I have it running in a water barrel and it stops after 20 minutes every time. Excellent water flow. Starts and runs fine until then. No alarms ever. Suspect FSM problem. Mechanic coming over to watch it fail. Don, what instruments/steps should he use to diagnose problem?

[EuropeanAM]

Be glad to help- could you verify the serial number (that one does not exist)?

[57slab]

s/n above off my OH title. Checked motor. "D" is a "B". So, s/n is 1B738278. When ign key turned 'on', a pump in FSM runs for about 5 seconds. Mechanic took boat to his shop w/o seeing motor quit. Said test in water barrel no good. Is there a procedure to test FSM?

[rickdb1]

If it's a 4 stroke, my money would be on the FSM. Float sticking or bad reference tube. Replaced the innards on mine with a kit from Merc. this last summer with similar symptoms. After reading too many stories about the pumps going out, I carried a fuel primer bulb and a couple of clamps to splice it into the fuel line. Just had to have someone pump the bulb occasionally to get fuel to the pump and it got me home. My understanding is that the new pumps are totally different design and eliminate the problem.

[EuropeanAM]

Have seen some problems with the FSM Float Switches- and it controls fuel pump functions (or lack of function in the case of a failure). CAN be intermittent.

Your dealer should reference SB 2009-09 for troubleshooting steps.

[57slab]

If it's a 4 stroke, my money would be on the FSM. Float sticking or bad reference tube. Replaced the innards on mine with a kit from Merc. this last summer with similar symptoms. After reading too many stories about the pumps going out, I carried a fuel primer bulb and a couple of clamps to splice it into the fuel line. Just had to have someone pump the bulb occasionally to get fuel to the pump and it got me home. My understanding is that the new pumps are totally different design and eliminate the problem.

Thanks Rick, 25 yrs ago used that trick to get to parts store when fuel pump on truck failed. Clark Hill Lake

[57slab]

Thanks for your help Don! Will file a report on the remedy.

[57slab]

Mechanic reports bad float in Fuel Supply Module, lift pump marginal, tubing and seals brittle. Injector pump good. Direction to him; replace everything in FSM except injector pump.

[rickdb1]

[57slab]

Problem solved, motor runs without stopping. Replaced lift pump, fuel level switch and associated tubing in FSM. High pressure pump checked good at 50 psi. Thanks for all the support. Next issue is disintegrated trolling motor plug, but that's another board.

[rickdb1]

I'm a little surprised Mercury didn't put out a recall on this one. I know they issued a service bulletin, but repairing a part that is know to (and will) fail should have been replaced,warranty or not. I replaced the guts on mine 2 years ago and and have read countless other situations where the pump was the cause. I know all makers do this, but it would have been nice to have it fixed before it failed. I see where they updated the pump so there is no more float or problems. So somebody knew something was going on. That said, if that's the worst thing that happens to mine, I can live with it. But I sure am glad I had the primer bulb with me to get me home. Was about 10 miles. Lot of rowing!! End of rant..