Nissan 40 running/idling rough.

[BobSim]

Hello, this is a 2005 model# ns40D2, serial# 023462XE. The engine was purchased new in 2007 and has around 150 hrs. on it.
My problem is not fuel related. The engine idles rough and frequently dies, runs rough most of the time. Occasionally it seems to run smooth but at the same time will not exceed 4500 rpm. I have changed plugs, tried a higher octane and have thoroughly checked my fuel system. I do use an additive (startron) for ethanol issues. The fuel filter on engine is good.
Any advice would be appreciated as the shop has a two day wait.
Also have noticed the tach. will malfunction intermittently when engine runs rough. Thank you.

 

[TOHATSU GURU]

Re: Nissan 40 running/idling rough.

Run the ignition tests as found in your service manual.

 

[deejaycee_2000]

Re: Nissan 40 running/idling rough.

check stator and coils ...

 

[Mas]

Re: Nissan 40 running/idling rough.

I know you said fuel is not the issue, but what have you done to eliminate fuel?

What is your compression on each cylinder? Also, do a spark gap check, see if the spark is strong and blue and is able to jump a 7/16 inch gap. When it is running rough, try pumping the primer bulb on your fuel line to see if that helps or makes it worse. If so, look to the fuel pump.

MAS