90 EFI 4STROKE Throws a Baby Fit

[duck48]

2011 90 EFI 4 Stroke (serial #1B844587) that I bought new on a pontoon, and has 115 operating hours. Engine has been perfect since new- runs like a sewing machine. It has been to a Mercury dealer every yea the start of pontoon season for all maintenance (oil/filter/gearlube/plugs/impeller). Yesterday was it's first day out for the year and it ran flawlessly for over an hour as it always has. After parking for about an hour & restarting/idling in gear, suddenly began to idle really, really rough, before dying. It would restart briefly and run for about 10 seconds (rough) before dying. It will not take throttle and the last start it backfired violently enough through the breather that it actually blew some foam off of that piece of crap airfilter. All of this was very sudden, without warning. Fuel supply is fresh, and treated. Alarm did not sound. Any ideas? Would it have set a code?

[EuropeanAM]

Since your engine is still covered under Platinum Product Protection, it would be BEST to get it in to an Authorized Mercury Dealer for inspection.

While there are a number of possibilities... a few of the more likely ones would include:

-Fuel contamination/water present
-FSM Reference hose
-FSM Float Switch
-Map Sensor

There are, of course, other possibilities... your local dealer should be able to locate the problem, and determine quickly if it's a Defect in a covered component.

[duck48]

You are correct Don- it's under Platinum Protection, and it is at a Mercury dealer now. I was just curious as to what your thoughts might be. I will let you know what comes of it........

[duck48]

And by the way Don- please allow me to personally thank you for your response. You do SO much for everybody here, and I know it takes a lot of your time to always respond. You are priceless to this forum- don't know what we'd do without you!

[EuropeanAM]

Best of luck... be sure to report back after the problem is located (always good to hear the resolution).

[duck48]

You were correct Mr Don......FSM Float Switch was the culprit. One more question....I understand that they have re-designed what i'll call the 'air filter' (i.e.the crappy desentigrating foam) . The last time I started the engine, it backfired (for lack of better term) through it so bad that it blew out section of foam. Should I expect my Platinum coverage to replace it as well?

[EuropeanAM]

If it was damaged as a RESULT of a covered component (such as the FSM float switch), it SHOULD be covered.

Otherwise, filters are normally considered a Maintenance Item.

[duck48]

Don- just an FYI. Mercury covered the float switch and an "updated" air filter. She's running like new again

[EuropeanAM]

Glad to hear it!

[Turnertech41]

Reminds of me of the old hot rod days.. The old edelbrock foam airfilter. One backfire, they burned up and sucked down the carb throats!