Nissan 9.9hp 4stroke starting problems!!! Help!

[dustbear]

I am at my wits end with this motor. The motor will only crank if I cover the air intake with my hand and try to crank it. Once I take my hand off the intake it will run for a few seconds then die. I have cleaned the carb, checked all lines to make sure there is fuel getting to the carb and replaced the bulb in the fuel line from the tank. It seems like I may have a vacuum leak but I don't know where it could be coming from because I have checked everything. Idea???

 

[dustbear]

It is a 2004 model nissan 9.9 4stroke with electric and pull start.

 

[Sea Rider]

Why do you need to crank engine with hand, should use choke and start as per owner's manual indication. You could have fuel connectors o'ring issues, worn, dried, lets air in....

Happy Boating

 

[Star]

I had this same type of problem with a 15hp mercury 4 stroke. If you use partial (manual choke) can you keep it running kind of rough for awhile? Open the throttle a bit to get to 2000 rpm while you open the choke. The idle circuit is a real pain to clean on these motors. Some can succeed just running Seafoam through it but you really should remove the carb, Disassemble the carb removing all plastic and rubber parts, and jets. Soak for 3 to 4 hours in Berrymans Chem Dip from Walmart. I cleaned mine 3 times before I got it right. Now it purrs like a kitten.

 

[pvanv]

What method did you use to clean the carb?

 

[dustbear]

Why do you need to crank engine with hand, should use choke and start as per owner's manual indication. You could have fuel connectors o'ring issues, worn, dried, lets air in....

Happy Boating

I do not crank it by hand I use the electric start. This motor does not have a manual choke. It has an Auto-by-starter that works as a choke.

 

[dustbear]

What method did you use to clean the carb?

I only have taken the carb apart and cleaned the jets I have not dipped the carb yet. I am guessing that should be my next move.

 

[dustbear]

I have cleaned the carb with chemdip and it seems to be working ok right now. I am gonna let it sit overnight and try to crank it in the morning.

 

[pvanv]

I have cleaned the carb with chemdip and it seems to be working ok right now. I am gonna let it sit overnight and try to crank it in the morning.

Your symptoms seem carb related, so if it works better, cool. If it is only somewhat better, dip it again, blow out all passages with generic aerosol carb spray, reassemble, and you will probably be good to go.

In the future, if you will not be using the motor the next day, allow the carb to run out of gas at the end of the day, to reduce varnishing. We have two of these on "barges" and they work flawlessly, as long as we don't allow the carb to sit too long (with gas in it) without running.