8hp nissan NS8B fuel delivery and carb ?

Hello Guys ,

Great forum -glad i found it.

I have an 98' 8hp 2cycle that doesn't seem to want to pump fuel to the carb very well ,i changed the diaphram gaskets and it worked better for a short while -but now not pumping very well.
Also it seems to flood and wet the plugs easily ,i friend and shade tree mechanic adjusted the carb [his son has the same motor] .
Could someone give me a baseline on how many turns in or out with the carb screws please.
Should i buy a carb rebuild kit ?
The engine will purr like a kitten [sometimes] and not run others or purr like a kitten for two miles then quit-i've gotten good at rowing my Gheenoe 13'.
Thanks for any help.
Mike

Re: 8hp nissan NS8B fuel delivery and carb ?

The fuel pump is vacuum/pressure-operated, and mounted on the carb on those models. Very reliable. A malfunctioning fuel pump would be causing you to starve for fuel -- not flood and wet out the plugs -- which is caused by excess fuel, typically from a bad needle/seat in the carb. So your description has conflicting symptoms. I suspect that the pump was OK all along, and you probably need to go through the carb properly. That is... disassemble it and clean it in a carb soak cleaner-bath, then rinse/blow it out and reassemble it.

But we are getting the trailer before the boat (or is that cart before the horse ... Get a Factory service manual from any dealer, and go through the diagnostic checks for both ignition and fuel. That book will also detail the initial settings for carb screws -- so that, after cleaning/rebuilding the carb, you can then dial-in the idle mixture and speed.

Re: 8hp nissan NS8B fuel delivery and carb ?

Thank you Paul !!

10-4 on the manual and soak.