I've got an 87 model 25HP Nissan that I'm trying to figure out why it runs rough at idle through 3/4 throttle. The motor runs great wide open, and does not miss a beat. Here is what i have done so far.
1. Cleaned Carb (three times), there is not a spot of anything in it.
2. Checked for air leaks by spraying carb cleaner around the carb. It quits (stalls) when I spray around the butterfly spindle. There is very little play around it. I was told this was normal, even if the carb was new.
3. Checked Compression, it's 125 on both cylinders. I am in the process of running Yamaha Ring Free through it to see if it has some carbon, or a stuck ring but compression seems to be ok.
4. Change plugs, both are a light - Med brown.
Primer bulb stays hard at all times, pumping it does nothing when it's running rough. When you are running WOT and pull back it seems to be missing on a cylinder (or both) it cuts in and out, but never quits (even if left idling for a long period of time.
What else can i check
-Chris
1. Cleaned Carb (three times), there is not a spot of anything in it.
2. Checked for air leaks by spraying carb cleaner around the carb. It quits (stalls) when I spray around the butterfly spindle. There is very little play around it. I was told this was normal, even if the carb was new.
3. Checked Compression, it's 125 on both cylinders. I am in the process of running Yamaha Ring Free through it to see if it has some carbon, or a stuck ring but compression seems to be ok.
4. Change plugs, both are a light - Med brown.
Primer bulb stays hard at all times, pumping it does nothing when it's running rough. When you are running WOT and pull back it seems to be missing on a cylinder (or both) it cuts in and out, but never quits (even if left idling for a long period of time.
What else can i check
-Chris