Small outboard motor

[HawkShot99]

I have a 4-stroke 9.9 HP Nissan outboard for my boat.

I want to give it a tuneup, to make it run better. When it is cold, it is extremely hard starting. I could sit there pulling for 5-10 mins. So I just give a quick squirt in each cylinder with starter fluid, and starts on 1-2 pulls. Then I need to sit there adjusting the throttle till it is warm, then it runs good. Starts with 1 pull when warm and idles no problem.

I do not have a manual for it so a few questions.....

-What can I do to make it start better? I am assuming clean out the carb?
-I am gonna get it new plugs.
-I do not know what to gap them at....Any ideas on getting it close?


Anything else it needs for a tune-up? I am not too good with engines/carbs.

 

[6Mile]

You pretty much have the basics covered if those do not help, the got to http://forums.iboats.com/ and see if there is anything that may help you. Post the model # and year and someone will come up with good info for ya. Kind of like here but for boats.

 

[800 RMK]

Run some Seafoam through it, it's a fuel additive. It actually works pretty good...........

 

[TWISTER]

check and adjust the valves.

Rob

 

[Wolfrun]

I have a 15 hp Nisson 4 stroke . After it was broken in it started hard cold until I discovered that to set the choke you open the throttle all the way and then back to start and it will start on the first or second pull. The manual doesn't tell anything about it either. I love the motor, it will troll all day on less than a gallon of gas.

 

[HawkShot99]

I gave it a tuneup and ran some sea foam through it for a few hours on the river. Ran great.

Although I forgot my # plates at home(it is a inflatable boat so I have removable plates) and the sheriff kicked me off the water......

 

[rare breed]

I gave it a tuneup and ran some sea foam through it for a few hours on the river. Ran great.

Although I forgot my # plates at home(it is a inflatable boat so I have removable plates) and the sheriff kicked me off the water......

thats just not right. he should have let continue practicing your seal traing.

 

[Gimpster]

Sounds to me like the slow jet in your carb is plugged or the fuel air screw needs to be set
Like some one suggested, put sea-foam in your tank, let it run for 20 minutes then leave the engine set for a few days. Usually takes care of the problem. If not, remove the airbox, once the engine is running take it up to around 2000 rpm hold the rpm there and cup the end of the carb with your hand (plug it off) and release before it dies. Do this a few times. If your lucky the proceedure will suck the obstructions through your idle circuit.
Also find the fuel air mixture screw, turn it in while idling until the engine 'sneezes' so to speak, you need to find the sweet spot, turn it slowly out until the idle raises and begins to slow again counting the turns. From that point of slowing while turning out, turn it back in half the amount of turns counted. Should cure your cold start problem.
I suggest decarbonizing the engine once a year for peak performance.