NS40C Running Issues

[jhultquist]

Hey everyone. I have a NS40C that I recently purchased. It will start up and seem to run great in the yard with the muffs on and when we get to the lake it will start right up and run great. I will run wide open 20-30min or so to a cove to fish and then we shut it off to use the trolling motor. After about 20min or so, it will start back up and idle fine, but then when I throttle it up it boggs down and dies. I can get it to start again but can only run it on idle speed or it will die.

I have replaced all of the fuel lines, cleaned out the carb, fuel pump was replaced by the previous owner, replaced the spark plugs, and the timing is adjusted correctly. I did notice that it came with an inline fuel filter, not the one that is between the fuel pump and the carb that is shown in the schematics.

Any help would be much appreciated. My family is tired of getting stuck out on the lake

 

[pvanv]

What method did you use to clean the carb? When it won't go above idel, do the plugs come out wet or dry?

 

[jhultquist]

What method did you use to clean the carb? When it won't go above idel, do the plugs come out wet or dry?

I took the carb apart and cleaned/soaked with carb cleaner & blew it out and put back together. If one of the jets was clogged, then would it run great at first?

Not sure if the plugs are wet or dry, I didn't take them out on the lake.

It runs amazing until I shut it off for like 20min or more.

 

[Sea Rider]

If all mechanically speaking it's OK, seems to be an electrical related problem, if with intermitent issues on any of the electrical components it's the worse nightmare to troubleshoot to find the culprit real fast...

Happy Boating

 

[jhultquist]

If all mechanically speaking it's OK, seems to be an electrical related problem, if with intermitent issues on any of the electrical components it's the worse nightmare to troubleshoot to find the culprit real fast...

If you think it might be electrical, where would you suggest that I start? It does have electric start but I have just been using the recoil starter. I haven't been able to get the electric start to work just yet.

 

[pvanv]

Full info on the ignition system is in the Factory service manual. As Luis suggested, those can be hard to find if it only fails hot... you need to have it failing and then test to see any problem. You could take the cowl off to cool faster, to verify whether it is actually thermal or not.

 

[Sea Rider]

You could Ohm troubleshoot all the lelctrical components individually and find them to be working OK in the factory range, but as Paul says misses when overly hot it's a different scenario and hard to diagnose properly. If having a multitester handy can post the Ohm info for you, let me know.

But much better would be to count with a DVA multimeter to troubleshoot each electrical component output by pulling the rope to check if inside the factory electrical specs.. A motor stopping to work on a constant basis will tire and bore anyone specially the falily real fast..

Happy Boating