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Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3981
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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2008 merc. 115hp 4 stroke efi. motor sat for about 2 years,

Customer Question

2008 merc. 115hp 4 stroke efi. motor sat for about 2 years, low hr motor,( thinking less than 50). At the start. looks like all was gas ran dry before storing, Tank appeared empty. Put fresh gas in tank, started up got it running, idle fine on hose, several minutes later boat mad a beep sound. River tested then, boat started up fine, sounded good, applied good amount of throttle and after about 2 minutes engine made 4 beeps and automaticly went into idle mood, pulled throttle into neutral and then back into gear ran good until another 2 minutes or so and Beeped again. did the same same over and over.
JA: Sometimes boat issues seem like they'll be really complicated, but end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Is there anything else the Marine Mechanic should be aware of?
Customer: ok
JA: What else should I tell the Marine Mechanic?
Customer: thats pretty much it
Submitted: 5 months ago.
Category: Boat
Expert:  Charles replied 5 months ago.

Hello, my name is***** will assist you.

Expert:  Charles replied 5 months ago.

There are two pumps inside the FSM on your engine, one is high pressure feeding the injectors the other is a boost pump drawing fuel from the tank. Without scanning the engine I would say the running issue and the alarm are due to the boost pump timing out. This would trigger the guardian system to slow the engine down. Bringing the throttle back to idle and allowing the FSM to fill again would allow just a few minutes of higher RPM. To test this, you will need to remove and open the FSM on the engine, then apply 12V directly to the boost pump and check its running. With the boat sitting that long, I would also replace the fuel line from the boat to the engine and all fuel filters.

While the FSM is open, the float should be updated and the MAP reference hose should also be replaced. This will ensure that there are no issues with them going forward.