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Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3714
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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I have a 201 ho Mercury jet drive engine stuck in limp mode.

Customer Question

I have a 201 ho Mercury jet drive engine stuck in limp mode. How to reset it?
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so the Marine Mechanic can help you best.
Customer: Was traveling on lake in my 2004 Mercury powered jet drive boat heavily loaded with passengers. Had throttle wide open when it went into limp mode. Do not know how to reset it.
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: No
Submitted: 11 months ago.
Category: Boat
Customer: replied 11 months ago.
That was 210 hp not 201 ho.
Expert:  Charles replied 11 months ago.

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

Expert:  Charles replied 11 months ago.

The guardian system on Mercury engines wil reset once the condition clears or the key is cycled. If you are still getting the alarm, make sure that the engine is not overheating and that the oil tank on the engine is full. If those items are both good, i will need the serial number to dig deeper into the engine with you.

Customer: replied 10 months ago.
Thanks. Are these usually the only two things that will initiate the limp mode? Is there possibly a compartment Fan/Fume switch somewhere that will do the same?
Expert:  Charles replied 10 months ago.

If you could provide the serial number from the engine, I can get you all the causes for the alarms.

Customer: replied 10 months ago.
Attached is a picture of the sticker with the serial numbers. Thanks for any help you can offer.
Expert:  Charles replied 10 months ago.


The alarm if a beeping tone would be for low oil on the tank of the engine. If the tank is actually full, disconnect one of the wires going to the cap, if the alarm stops, replace the cap. If the alarm is a solid tone, that is for overheating, inspect the cooling system on the engine and make sure that it is all clear, including the overboard at the rear of the boat.

Customer: replied 10 months ago.
Trouble is, I haven't heard an alarm sound, but will only run fast enough to limp in. When it first happened we had the boat fairly loaded and crusing pretty full open, It just Shut down to a low speed. Seems to start ok but will not take throddle up. Let me ask something about the primary fuel pump (electric) When I turn the switch on I just get a little blip of voltage to the pump. It doesn't run long enough for it to build any pressure on the system. We had taken the fuel line loose to the engine driven pump and there seemed to be very little fuel in the line. The electric pump works and pumps if I jumper it. My question is what is supposed to bring the electric pump on and how long should it run? Is it supposed to continue running while the switch is turned on?
Expert:  Charles replied 10 months ago.

It is just a booster pump to help the pulser pump get fuel to the carbs. The ECM is what tells it to come and turn off.

When you turn the key on, do you hear a test beep?

Customer: replied 10 months ago.
the electric pump is supposed to run continually when boat is running? Sounds like the ECM may be bad. The test beep has been working, not sure it does now. I'll check it.
Expert:  Charles replied 10 months ago.

No it is only for priming to assist starting.

Customer: replied 10 months ago.
When the key is turned on the primer pump only energizes for a fraction of a second, just enough to blip on. It should do more than that, correct? Sorry to keep bothering you with it, it just looks like the pump would run long enough to build pressure to the other pump. It doesn't even prime itself.
Expert:  Charles replied 10 months ago.

Have you tested to see if it is running when cranking the engine over. That would mean removing the discharge line from that pump, placing a container under it, then crank the engine over to see if you get any fuel from it?

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