ns70a oil fouling plugs...

[hamegg3]

just the facts.....

1. bought used ns70a 1 year ago
2. ran perfect for 1 year
3. this summer started oil fouling plugs
4. changed plugs
5. ran fine for 1st half of fishing trip
6. ran wot back to boat ramp
7. fouled top plug, would not start back up to load onto trailer. lots of sneezing and just wouldnt crank.

Questions: read on motocross 2 cycle forum that idle air adjustment fixes this problem. could spraying wd 40 on linkages and screws cause them to vibrate out of adjustment??? Why is oil covering everything inside cowling?
Why when idling around does the motor surge and stumble and surge again?
ANY HELP WOULD BE GREATLY APPRECIATED, ----NEED TO FISH!

 

[pvanv]

Re: ns70a oil fouling plugs...

You need to diagnose the problem. The Factory service manual is a good investment. Could be ignition-related, but likely a fuel problem. Test/verify/clean/adjust everything in the fuel system. Pay special attention to the top carb. Likely needs a good carb cleaning. The oil is likely residue from fuel. If you are way too rich, due to a sticky float, it could cause those symptoms. Or you could have a cracked reed, causing excess spitting from that carb.

Keep in mind that many parts for the 70A are getting rare. Proceed with caution to avoid spending too much money on a motor that has a limited remaining lifespan.

 

[hamegg3]

Re: ns70a oil fouling plugs...

thanks for the reply, I have found after taking front cover off carb that fuel is spitting from the carbs by the throttle plates. could this overload the combustion chamber with fuel fouling the plugs>?

thanks for the help!

 

[pvanv]

Re: ns70a oil fouling plugs...

You've started the diagnosis, and have another symptom -- spitting. That probably resulted in the oil residue inside the cowling. Now you need to complete the diagnosis. Varnished carbs, coked-up combustion chambers, or cracked reeds could cause your symptoms. Especially with today's poor gas quality, I would clean/inspect/adjust/sync all 3 carbs first, as 80% or more of current OB problems are carb related.

Do you always run the carbs out at the end of the day? You should. Were the carbs drained for off-season storage? They should have been. If the fuel sits in the carbs for a week, varnish starts, and could be your root problem.