ns8b possible carb issues

Hello, I'm new to the forum and as I'm sure you see all to often, I found the site because I have a problem... I bought a small boat with an '01 ns8b on it. The motor appears to be very low hour (or at least well cared for) and in general starts and runs great however, when you wind it up to around the top 20% of the rpm range it doesn't want to rev clean. From back in my dirt bike days that seems to me like the main jet needs to be leaned out a bit. I pulled the carb apart and it all looks clean and in good shape. I'm at around 5,200 ft elevation or so and I have no idea where this motor originally came from so, it very well could be jetted for sea level. Does this sound like a logical first step to try and if so, does anyone know what would be a good size main to run at 5-7,000 ft? Thanks for any help you can give

Re: ns8b possible carb issues

i am unclear of how elevation affects motors but i have heard these carbs do have areas that cant even be cleaned that get clogged. It comes from trolling as kickers. This is what another guy posted in one of my threads...

"One other con for the Honda is that the carb passages will plug up very quickly with today's fuels unless you continuously use a fuel stabilizer. In extreme cases you may have to buy a new carb as some of the blind passageways cannot be cleaned out sometimes, even using an ultrasonic cleaner."

Re: ns8b possible carb issues

Your Nissan requires high altitude jets at that elevation. They are available from any Nissan or Tohatsu dealer. Since you will have to take the carb apart to put in the new jets it would make sense to clean the carb at the same time.

Re: ns8b possible carb issues

whoops... didnt see it was a nissan

Re: ns8b possible carb issues

Thank you. That's what I thought. Hopefully that's it