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Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 10898
Experience:  40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
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I recently purchased a 2010 Sea Ray with a 2010 Sear Ray

Customer Question

Hello, I recently purchased a 2010 Sea Ray with a 2010 Sear Ray Mercruiser 4.3 TKS (with 12.5 hours) which I was told had 1-2 year old gas, probably ethanol gas. I changed the water separator and drained the old fuel and put in fresh 100% gasoline. I also added a can of Sea Foam to the fuel tank.
The boat is a little hard to start but once warmed up it idles just fine at 500 rpm's in and out of the water. Out of the water I can rev up the engine and it sounds fine, with no hesitation. In the water (under load) the engine boggs down above 2k rpm's, like its not getting enough fuel. I have read its likely either the fuel pump or the carb is dirty. Do you know how I can diagnose the problem to find out which it may be?
Also if I remove my carb to be rebuilt by a third party are they typically preset before it gets reinstalled or does a carb need to be "fine tuned" once its mounted back to the engine for correct operation?
Submitted: 1 year ago.
Category: Boat
Expert:  Tan replied 1 year ago.
Hello. My name is ***** ***** I will be assisting you today.
Since the engine does run you can eliminate the fuel pump. So that leaves the carburetor. The boat sitting for that long will have a dirty carb. What happens is when the boat sits the volatile part of the fuel evaporates leaving a gummy residue in the bottom of the carburetor. Now all the jets are in the bottom of the carb which is why the engine will not run over 2000 rpms. The engine is starving for fuel.
The engine will rev up with no load as it doesn't take much fuel to rev the engine but when you put it under a load it requires allot more fuel and the carb being clogged won't allow enough fuel to run the boat.
So what you need to do is have the carb removed, disassembled and cleaned and a carb kit installed. The carburetor is initially set but does need to be fine tuned once the carb is installed. The engine will run on initial setting just not as well as it should.
The TKS carb does require a special tool (866201) for setting the idle jet which only a dealer will have.
The carb is something you can do your self if you have done carburetors before if not you will have to take the boat to a dealer.
Post back with questions.
It may take more than one reply to get you all the info you need so please post back with questions.

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