2006 Mercury 9.9 4 stroke starts then shuts off

[hunt2011]

Hello.. I have a 2006 Mercury 9.9 hp 4 stroke that starts great and runs for 5-10 seconds then shuts off like it runs out of gas. It starts right back up and runs for 3 sec then off. Then if I try to start again it doesn't. If I let it sit for a day it will start and run for 5-10 seconds then shuts off, etc, etc. Any ideas? If I disconnect the fuel line going into the carb and squeeze the primer bulb gas squirts out easily so I think the line is ok. Is it the carb, or maybe the fuel pump? When I disconnect the fuel line coming from the fuel pump and start the motor, gas barely trickles out of the hose, should the fuel pump be pushing more fuel out? I don't know alot about motors.

 

[Star]

Re: 2006 Mercury 9.9 4 stroke starts then shuts off

Hi hunt,
Once you fill the carb bowl with primer bulb the motor should run at idle for more than a minute with the fuel line completly disconected. Read the 33 thread post by bluechevyy. As he found out after taking it to a dealer the carb is the problem. The carb can be cleaned in most cases.
The engine will run if you feed more fuel with the throttle or partial choke because the idle circuit is blocked somewhere. A strong carb cleaner should fix this. It is recomended that you get a carb rebuild kit and if you get one buy Mercury not Seaira. It can be done without a kit but it is better to replace the small filter, needdle, and idle adjustment. The idle adjust is hidden behind a brass cap that has to be drilled and removed. Good luck on this, I had the exact same problem this spring!

 

[CharlieB]

Re: 2006 Mercury 9.9 4 stroke starts then shuts off

Check the crankcase oil.

Is the level high? Does it smell like gas?

Remove the two screws holding the fuel pump in place but leave the hoses ON. Pump the primer bulb while watching the backside of the fuel pump for ANY fuel leaking, indicating a pin hole in the diaphragm. If leaking, order/install a fuel pump or rebuild kit.

If ANY fuel is in the crankcase oil, change oil and filter BEFORE running the motor!

 

[hunt2011]

Re: 2006 Mercury 9.9 4 stroke starts then shuts off

Thanks for the replies! I will look into your suggestions when I get to my boat this weekend.

Star - Do you mean disconnect the fuel line from the carburetor and it should run for more than a minute? I think I tried this but I will check it again. I might try a strong carb cleaner first before rebuilding..do you mean the carb cleaner that you add to the fuel and let it run through? I dont know if that will work if my motor only runs for 5 seconds. Is there a way to clean the carb without taking it off and apart?

Charlie - I will try checking the fuel pump like you said. As for the crankcase oil, do you know how I can check the level and if there is gas in it? I have only ever changed the engine oil and the lower gear oil in this motor. I just got it last year and Im not very familiar with outboards. I didn't think it had any oil filters.

Also, when I first started it this year (it started right up) I noticed some gas running down the shaft but this only lasted a few seconds, and afterwards the motor ran fine for maybe a half hour before it shut off and I began having these problems. I think the gas came from the vent tube coming off of the top of the carb but not sure.

 

[CharlieB]

Re: 2006 Mercury 9.9 4 stroke starts then shuts off

4 stroke motors have a dip stick, just like a car. Oil level should not be any higher than the full mark.

Sniff the oil on the stick, if it is high you may smell gas.

 

[Star]

Re: 2006 Mercury 9.9 4 stroke starts then shuts off

The idle circuit passages run across the top of the carb so that it has to be inverted or force cleaner into the small hole you see at the top of the venturi after the throtle buterfly.