2006 Nissan 9.8 HP dies

[rdthoms]

I have a 2006 Nissan 9.8 that does the following:

1) won't run at low idle, really rough and dies
2) when started and run at fast idle it will run smooth for a bit and then die (almost like fuel was cutoff)
3) runs OK (but not great) at higher speeds

Here is a video link that shows #2 problem which I hope should provide the most info to help me diagnose:
https://goo.gl/photos/Zkuuov1fjQFQgshb7

In this video the engine is warm and choke off and starts on first pull (with throttle partially open). Throttle is immediately turned back to fast-idle and then hands off. You'll see the engine runs for about 15 seconds and then just quits fairly suddenly with no coughing or sputtering just stops.

After that you can start it again and go through the same thing. The fuel bulb stays firm throughout. I'm wondering if the float needle is getting stuck or something?

I had a similar problem (reported here: http://forums.iboats.com/forum/engi...8275-nissan-9-8-4-cycle-won-t-idle-gas-in-oil) 6 months ago and thoroughly cleaned the carb (tear down and dip) but that did not solve the issue. Only when a friend adjusted some of the linkage on the carb did we get it to idle properly. I tried making adjustments this time but that is not helping.

 

[TOHATSU GURU]

It's a safe bet that you need to correctly clean the carburetor before you do anything else.

 

[pvanv]

It's a safe bet that you need to correctly clean the carburetor before you do anything else.

Yep. Likely still a low-speed carb circuit issue. After complete carb disassembly and 4+ hour soak in carb dip, then blow out all passages with generic carb cleaner. Use a whole can, and hold the tip of the straw tight to the passages to get maximum turbulence and pressure from the spray. When reassembling, verify correct float valve operation. Of course also verify correct crankcase oil level, and make sure you have Fresh gas and good plugs.
Setting the throttle rod properly requires that the carb low speed idle is working correctly and the stop screw set properly first. If you fiddle with that linkage before having the carb clean and working right, you may mask a low speed issue by actually holding the throttle slightly open. Once you know with certainty that the carb is right, then set the throttle grip to idle, and then adjust the throttle rod for almost zero play with choke off. If there is too much play, advancing the grip to fast idle will only take up the slack in the linkage, but not open the throttle plate to fast idle. If the rod is adjusted too tight, the throttle stop screw will not be touching the bellcrank, and your idle will actually be set by that rod -- which is likely what happened back in the Spring.

 

[rdthoms]

Well it did the trick: disassemble carb,, ~20 min in ultrasonic hot soak, 5 hours in carb dip, 1 can of carb cleaner, 1 carb rebuild kit (float, needle, gasket, diaphragm). Bolted it back on and seems to run well (idles well at least, I could not take it out today).