2003 40 HP Nissan NS40D2 Trouble Idling/Bogging Down

Nasonshine

Cadet
Joined
Aug 20, 2015
Messages
18
Overall this engine has been great to me- used it year round since acquiring it 5 years ago, consistently 3-5 days a week commercial fishing etc...

Had a bout with bad gas a few months ago- changed fuel filter- definitely some water in there, changed fuel filter/separator and oil filter attached to the engine itself- changed plugs, new gas tank, fuel lines?..definite improvement but still had trouble idling and have always had to start the engine with key choke and neutral warmup lever up (even prior to bad gas and even after warm up engine would not start without either) 2 days ago noticed gas coming out of lower carb, could prime the gas bulb and would spill out etc?. bought carb kit and installed/cleaned carbs (kit did not include gaskets/parts for fuel pump which is attached to lower carb)- started it in the yard and it cranked right up without neutral warm up lever at all which was a first- sounded great

took her to the boat ramp for a flounder gigging mission this evening and she again started great without choke or warm up lever?..got past no wake zone, ran her 3/4 speed for 10 minutes everything sounding great (fresh non ethanol fuel in tank)- decided to open her all the way up and she bogged down and shut off??tried to start again but wouldn't- used choke and neutral warm up lever and still nothing- initial thought was it was flooded? Gigged a while and then tried to start and she did- but only with the key choke and neutral warm up lever up like before, along with bad idling/shutting off in neutral...no gas overflowing from carb however so they seem to be holding- (owners manual says to use the neutral warm up lever for starting but found it curious that i was back to where i was before carb kit installation/repairs)

any thoughts?
thanks in advance
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Welcome to Iboats,

That's a 3 cylinder OB right ? Right now has both idle and wot issues ? Have you tried other fuel line that's working in good cond. If your fuel line is that old as your OB, probably have worn, dried internal fuel connector o'rings, lests air in in fuel circuit and engine misses dies at wot. Is that OB used on salt or fresh water. If salt water use, do you flush it after each outing or stays moored and impossible to flush ?

Happy Boating
 
Last edited:
Top