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Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3715
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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Have a 150 verado that generally runs excellent. But recently

Customer Question

Have a 150 verado that generally runs excellent. But recently it goes into limp mode after the long 6 sec beep. It will never happen at idle speed but once rpm is up it happens. Not consistently though
Submitted: 2 years ago.
Category: Boat
Expert:  Charles replied 2 years ago.
Hello, my name is***** you for allowing me to assist you today.
What year is the motor?
Has any work been done to the engine?
What kind of boat is the engine on?
Customer: replied 2 years ago.
Hi Charles. The boat and motor are a 2012. The boat is a South Bay pontoon boat, 24'. The only work done to the motor was a "map sensor" they replaced last year on warranty.Runs great at idle speed, can troll around the lake for hours but as soon as I increase the speed it sporadically goes into limp mode. Once I power off and on then it's fine again. Prior to limp mode it sounds the 6 second solid beep. There is no consistency with regard to when it happens. Sometimes I can run at higher speed for 5 miles and other times it happens in seconds
Expert:  Charles replied 2 years ago.
Is there a primer bulb in the fuel line?
If you have SMartCraft gauges, what does the error text state?
Customer: replied 2 years ago.
Good day. There is no primer bulb, just a direct line. I do not have the gauges that state what the error code is. For extra information, there was stabilizer added to the fuel last fall and since there has been 2 tanks of fresh premium fuel ran through the motor. I have read online that there have been issues with the FSM (fuel supply module). Could this be the issue?
Expert:  Charles replied 2 years ago.
Yes it can totally be in the FSM. The issue that you are describing is what we call a danging float. At RPM the harmonics of the engine will alow the float to spin ion the shaft and actually ride up it. This will make the PCM think that the FSM is still full.
The alarm that you get is the lift pump time out. When the motor bogs down, the float then drops down, the pump turns back on and fills the FSM, Then the motor can take of again.

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