nissan 120 2 stroke

[dahnovka]

Nissan 120hp 2 stroke - starts great, runs great/revs up when out of water on a hose, but once boat in - runs rough a bit above the idle and only with choke full on .. any ideas what to look at? I’m new to outboards and it really feels like squirrels made a nest in lower unit so it floats and clogs something when in water...

 

[ct1762@gmail.com]

sounds like a carb problem. Remove and clean with an alcohol filled syringe and blow out all passages, particular attention to idle circuits.Are you checking to be sure it isn't overheating?

 

[pvanv]

Yep. Go through the fuel system. Sounds lean. Clean all carbs. Properly.

 

[dahnovka]

thank you for the advice!

turned out all linkage on carbs was way off-spec, top 3 out of 4 sparkplugs had no spark, 2 needle valves significantly worn, after clean up / adjustment / new plugs - started right away and ran great for a few days - now back to dancing with shaman drum to start when cold and runs/starts OK once it's going.

I'm not sure what's up with top cylinder, removing the spark plug cup when running makes very little difference in comparing to second/third/forth

 

[pvanv]

Check the electrics for #1 cylinder. Check top carb.

 

[Sea Rider]

If that motor has independent spark plug ignition coils, probably first cylinder coil is shot ?

Happy Boating