2006 Mercury 9.9 HP outboard - 4 stroke

dougd1

Seaman Apprentice
Joined
Jul 12, 2021
Messages
45
I bought a used 2006 Mecury 9.9 HP 4 stroke outboard motor. Am new to outboard motors, but I am having some issues with this motor. When I prime the motor (either with the priming bulb on the fuel line from the tank or the priming bulb on the motor), gas will eventually leak out of the carb. I replaced the fuel line from the on-board priming pump to the carb, but it still leaks when I press the priming pump (although not at much). Is this normal for outboard motor engines? I have also found the gasket between the carb and intake manifold not correctly in place. I am wondering if the carb needs a rebuild - are there carb kits available to do this?
The engine also has a tough time idling - if the idle is set too low, the engine stops when put into gear unless you give it lots of gas, which makes shifting into gear a bit traumatic. If the idle is set too high, the engine surges/hunts - cyclically revving up in speed and then coming down in speed. I am wondering if an orifice is partially plugged to cause this.
Any advice appreciated.
Doug
 

oldcab

Cadet
Joined
Oct 20, 2021
Messages
13
if you reckon the gasket is not correctly in place that would be the first place to check, if you got time, may as well restore the carby, should be plenty of kits for this, not exactly hard job, plenty of youtube videos, many reasons why carby leaking, try fixing the gasket first, if not, just restore it
 

dougd1

Seaman Apprentice
Joined
Jul 12, 2021
Messages
45
if you reckon the gasket is not correctly in place that would be the first place to check, if you got time, may as well restore the carby, should be plenty of kits for this, not exactly hard job, plenty of youtube videos, many reasons why carby leaking, try fixing the gasket first, if not, just restore it
thanks for responding. Have also been told that there are two small o-rings at the bottom of the carb where the priming pump line comes in that are likely worn. Any time I press the priming bulb, I can see fuel dripping from the carb. I had assumed it was the gasket between the carb and float assembly, but was not aware of these two small o-rings. They are apparently hard to find replacements for in the aftermarket.
Will remove the carb next week and have a go when I winterize the motor.
 

oldcab

Cadet
Joined
Oct 20, 2021
Messages
13
it's hard to say till you look at it, it could be a needle value for the bowl that is not sealing and causing the bowl to overfill etc

i'm sure most rebuild kit should have all gaskets and orings that you need in the pack, just shop around and check?
 

dougd1

Seaman Apprentice
Joined
Jul 12, 2021
Messages
45
it's hard to say till you look at it, it could be a needle value for the bowl that is not sealing and causing the bowl to overfill etc

i'm sure most rebuild kit should have all gaskets and orings that you need in the pack, just shop around and check?
Thanks, I will certainly do that. Are there any aftermarket sellers of these carb kits? I checked with a local mercury dealer here (Ottawa canada), and they are looking at a $135.00 price tag for a carb kit, which is a bit on the expensive side.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,852
Take it apart and look to see what you actually need !-----Did a carburetor cleaning on a 15 HP earlier this year ( northern Ontario ) no parts used.----Runs like a top once more !
 
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