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Ask Dominick Your Own Question
Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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I have an 2008 mercury bigfoot 50hp. Every since it was

Customer Question

I have an 2008 mercury bigfoot 50hp. Every since it was brand new it surges about 100 to 300 rpms between 3000 and 4000 rpms. I took it in once they said it was fixed came home still the same. 1 1/2 hours each way. Then I ran into a guy who said its the carbs and its costly to repair. So I left it alone. I had a coil go bad and while I was in there I noticed its fuel injection. So it can't be a carb issue. It runs smoothly at all other rpms and has plenty of power. It's almost like it loses a few hundred rpms and picks back up.
Submitted: 2 years ago.
Category: Boat
Expert:  Jason replied 2 years ago.

Hello my name is ***** ***** am I speaking with?

Surging just a few hundred rpms means an inconsistance fuel flow into the engine. It can means a few different things, but starting with the most basic, when was the last time all of the fuel filters were changed on the engine? This includes the filter inside of the vapor seperating tank on the engine. This is the one that dealers usually change out.

Customer: replied 2 years ago.
Why is it only between 3000 to 4000 rpms? Should it be all rpms¿
Expert:  Jason replied 2 years ago.

No not necesarily

Expert:  Jason replied 2 years ago.

Let me ask you something else, are you boating in a lake, or in a river or bay/ocean, where there are currents?

Customer: replied 2 years ago.
It is a lake. Like I said it's been like this since it was new
Expert:  Jason replied 2 years ago.

Has the engine been into the dealer, if yes, what have they told you?

Customer: replied 2 years ago.
It's an 1 1/2 hours away. I took it once and they removed the bulb and said there was a gas line pinched inside the engine. Got it home and it did the same. Been living with it every since.