Nissan 9.8 2013 4 stroke Idle

[Rick C]

The motor has less than 30 hours on it and performed fine until the last outing. Started right up with choke out but cut off when I choked back in. Never could get it to idle that day and ended up returning on the trolling motor. I have put it in a barrel and been trying to get it running with no luck. Changed the gas and added sea foam. Cleaned the fuel filter and cleaned the spark plugs which were pretty fouled. On starting it with choke, it starts right up and idles higher than it did before. Push the choke in a touch and it idles very fast, push in a little more and it shuts down. Any suggestions on where to go next?

 

[drb111]

I have the same engine and had the same problem. Make sure that you only have oil coming up to half to 3/4 up the dipstick. When mine idled roughly, I had oil over the full line on the dipstick and this was at about 15 hours. hanged the oil and reduced to roughly 5/8ths up the dipstick and problem solved. With few hours, the motor will continue to "make" oil. If that doesn't work then you may need a carb clean/ rebuild including a 4 hour soak to remove any "tarnish" that didn't burn off from the factory during break in. Good luck. These are great motors and I am on about 2 years with zero issues and a smooth idle.

 

[Rick C]

Thanks, heading out to do that. I did notice the oil level was slightly above the full line so hopefully that's it. Looked at the carb schematic and really don't want to open that up if I can get by.

 

[drb111]

Hopefully the oil trick works...rereading- your high idle may mean carb adjustment, but mine would choke out after I pushed the choke in also and the lower oil level worked.

 

[Rick C]

That didn't do it Dang it. The thing has barely been used, doesn't seem like it would fall out of adjustment. How difficult is it to pull and clean the carb? Looks like 2 bolts and the linkage but am real reluctant to dismantle one that new.

 

[drb111]

I had a shop clean mine. I used to clean my 1985 Johnson all the time and there are plenty of decent youtube on cleaning the tohatsu, but I am just not that handy. Although I don't think it is very difficult.

 

[pvanv]

/Soap Box On/

On any EPA-rated carbed outboard of any brand, you must reduce the chance of accumulating varnishing in the small passages of the carb. That means only running fresh gas (less than 30 days old), running the carb dry at the end of each and every day (unless you know you will be running tomorrow), running only non-ethanol fuel if available, and if for some reason the fuel is approaching, or might approach the 30-day age, running stabilizer in the fuel.

/Soap Box Off/

Once the carb is varnished, the only solution is a Proper cleaning. Not just a spray. (or replace the carb with a new one if the expertise/materials to clean is not available). In addition (separate issue), since all 4-stroke OB's make oil, the oil level must never be allowed to climb above full. Once the plugs are oil/carbon fouled, it is best to change them.

 

[Rick C]

Thanks for all the advice. Pulled the carb and cleaned the low speed jet and that solved it for now. I also ordered a water/particulate filter to mount back there.

 

[tommarvin]

Good for you, never run a 4-stroke without a 10 micron spin on water separator filter, or 2-stroke for that matter.

Have to keep the low speed jet(s) clean to idle smooth.

We have a 2-stroke, and don't get how or why 4-strokes OB's make oil ?

We empty the carb bowls, if were not going to use the motor a awhile, its so fast to do, sure helps.

We installed our bracket for the filter close to the motor on the side where the gas line goes to the motor.

 

[Sea Rider]

Much better is to consume fuel on carb bowl while flushing OB after use. Just disconnect engine connector, start engine and let die of fuel starvation. Removing fuel plug from bowl to remove fuel regularly will end damaging carb threads.

Happy Boating

 

[chanders]

I have that same motor. Right from the factory the motor didn't start easily. What I did was to remove the brass plug from the air mixture adjustment, (dril it out carefully). Turn that adjustment out about two turns, CCW, then turn down the idle a smidge. You can fine tune it on the water or in a bucket at home. Worked like a champ. Can gas it now without it bogging down. Runs much better. Also, it's very important to run the gas out after every use. Then drain the carb bowl. I put a paper towle under the carb, loosen the drain screw let any residual fuel drain out. Remember, this is very important.